CONTRIBUTING.md: Move to repo root, where it is more visible.

We found that many users found it difficult to locate this document.

Github supports it in the root, see:
https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/setting-guidelines-for-repository-contributors

3 files changed, 3 insertions, 88 deletions

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
deleted file mode 100644
index 5cf674ab10a..00000000000
--- a/.github/CONTRIBUTING.md
+++ /dev/null
@@ -1,85 +0,0 @@
-# How to contribute
-
-Note: contributing implies licensing those contributions
-under the terms of [COPYING](../COPYING), which is an MIT-like license.
-
-## Opening issues
-
-* Make sure you have a [GitHub account](https://github.com/signup/free)
-* Make sure there is no open issue on the topic
-* [Submit a new issue](https://github.com/NixOS/nixpkgs/issues/new/choose) by choosing the kind of topic and fill out the template
-
-## Submitting changes
-
-* Format the commit messages in the following way:
-
-  ```
-  (pkg-name | nixos/<module>): (from -> to | init at version | refactor | etc)
-
-  (Motivation for change. Additional information.)
-  ```
-
-  For consistency, there should not be a period at the end of the commit message's summary line (the first line of the commit message).
-
-  Examples:
-
-  * nginx: init at 2.0.1
-  * firefox: 54.0.1 -> 55.0
-  * nixos/hydra: add bazBaz option
-
-    Dual baz behavior is needed to do foo.
-  * nixos/nginx: refactor config generation
-
-    The old config generation system used impure shell scripts and could break in specific circumstances (see #1234).
-
-* `meta.description` should:
-  * Be capitalized.
-  * Not start with the package name.
-  * Not have a period at the end.
-* `meta.license` must be set and fit the upstream license.
-  * If there is no upstream license, `meta.license` should default to `lib.licenses.unfree`.
-* `meta.maintainers` must be set.
-
-See the nixpkgs manual for more details on [standard meta-attributes](https://nixos.org/nixpkgs/manual/#sec-standard-meta-attributes) and on how to [submit changes to nixpkgs](https://nixos.org/nixpkgs/manual/#chap-submitting-changes).
-
-## Writing good commit messages
-
-In addition to writing properly formatted commit messages, it's important to include relevant information so other developers can later understand *why* a change was made. While this information usually can be found by digging code, mailing list/Discourse archives, pull request discussions or upstream changes, it may require a lot of work.
-
-For package version upgrades and such a one-line commit message is usually sufficient.
-
-## Backporting changes
-
-Follow these steps to backport a change into a release branch in compliance with the [commit policy](https://nixos.org/nixpkgs/manual/#submitting-changes-stable-release-branches).
-
-1. Take note of the commits in which the change was introduced into `master` branch.
-2. Check out the target _release branch_, e.g. `release-20.09`. Do not use a _channel branch_ like `nixos-20.09` or `nixpkgs-20.09`.
-3. Create a branch for your change, e.g. `git checkout -b backport`.
-4. When the reason to backport is not obvious from the original commit message, use `git cherry-pick -xe <original commit>` and add a reason. Otherwise use `git cherry-pick -x <original commit>`. That's fine for minor version updates that only include security and bug fixes, commits that fixes an otherwise broken package or similar. Please also ensure the commits exists on the master branch; in the case of squashed or rebased merges, the commit hash will change and the new commits can be found in the merge message at the bottom of the master pull request.
-5. Push to GitHub and open a backport pull request. Make sure to select the release branch (e.g. `release-20.09`) as the target branch of the pull request, and link to the pull request in which the original change was comitted to `master`. The pull request title should be the commit title with the release version as prefix, e.g. `[20.09]`.
-6. When the backport pull request is merged and you have the necessary privileges you can also replace the label `9.needs: port to stable` with `8.has: port to stable` on the original pull request. This way maintainers can keep track of missing backports easier.
-
-## Criteria for Backporting changes
-
-Anything that does not cause user or downstream dependency regressions can be backported. This includes:
-- New Packages / Modules
-- Security / Patch updates
-- Version updates which include new functionality (but no breaking changes)
-- Services which require a client to be up-to-date regardless. (E.g. `spotify`, `steam`, or `discord`)
-- Security critical applications (E.g. `firefox`)
-
-## Generating 21.11 Release Notes
-
-(This section also applies to backporting 21.05 release notes: substitute "rl-2111" for "rl-2105".)
-
-Documentation in nixpkgs is transitioning to a markdown-centric workflow. Release notes now require a translation step to convert from markdown to a compatible docbook document.
-
-Steps for updating 21.11 Release notes:
-
-1. Edit `nixos/doc/manual/release-notes/rl-2111.section.md` with the desired changes
-2. Run `./nixos/doc/manual/md-to-db.sh` to render `nixos/doc/manual/from_md/release-notes/rl-2111.section.xml`
-3. Include changes to `rl-2111.section.md` and `rl-2111.section.xml` in the same commit.
-
-## Reviewing contributions
-
-See the nixpkgs manual for more details on how to [Review contributions](https://nixos.org/nixpkgs/manual/#chap-reviewing-contributions).
diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 51a9e8bb21f..27d959410b6 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -23,8 +23,8 @@ Reviewing guidelines: https://nixos.org/manual/nixpkgs/unstable/#chap-reviewing-
 - [ ] Tested via one or more NixOS test(s) if existing and applicable for the change (look inside [nixos/tests](https://github.com/NixOS/nixpkgs/blob/master/nixos/tests))
 - [ ] Tested compilation of all pkgs that depend on this change using `nix-shell -p nixpkgs-review --run "nixpkgs-review wip"`
 - [ ] Tested execution of all binary files (usually in `./result/bin/`)
-- [21.11 Release Notes (or backporting 21.05 Relase notes)](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md#generating-2111-release-notes)
+- [21.11 Release Notes (or backporting 21.05 Relase notes)](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#generating-2111-release-notes)
   - [ ] (Package updates) Added a release notes entry if the change is major or breaking
   - [ ] (Module updates) Added a release notes entry if the change is significant
   - [ ] (Module addition) Added a release notes entry if adding a new NixOS module
-- [ ] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md).
+- [ ] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md).
diff --git a/.github/workflows/backport.yml b/.github/workflows/backport.yml
index 5b38b94bd6d..bea970f02d4 100644
--- a/.github/workflows/backport.yml
+++ b/.github/workflows/backport.yml
@@ -25,5 +25,5 @@ jobs:
           pull_description: |-
             Bot-based backport to `${target_branch}`, triggered by a label in #${pull_number}.
 
-            * [ ] Before merging, ensure that this backport complies with the [Criteria for Backporting](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md#criteria-for-backporting-changes).
+            * [ ] Before merging, ensure that this backport complies with the [Criteria for Backporting](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#criteria-for-backporting-changes).
               * Even as a non-commiter, if you find that it does not comply, leave a comment.