Add: GoEndian dependancy

I'm a little confused as to why this buils and runs on darwin, but fails to
build without it on linux. The error was:

```go/src/github.com/gxed/eventfd/eventfd.go:17:2: cannot find package "github.com/gxed/GoEndian" in any of:```

1 files changed, 9 insertions, 0 deletions

diff --git a/pkgs/servers/holochain-go/deps.nix b/pkgs/servers/holochain-go/deps.nix
index 31e5c2c11a7..bad01c01a6b 100644
--- a/pkgs/servers/holochain-go/deps.nix
+++ b/pkgs/servers/holochain-go/deps.nix
@@ -181,6 +181,15 @@
     };
   }
   {
+    goPackagePath = "github.com/gxed/GoEndian";
+    fetch = {
+      type = "git";
+      url = "https://github.com/gxed/GoEndian";
+      rev = "0f5c6873267e5abf306ffcdfcfa4bf77517ef4a7";
+      sha256 = "0fn28h9gs1finrpfs388a3ycavlcf3qylsn803cflmrwaj5piqia";
+    };
+  }
+  {
     goPackagePath = "github.com/huin/goupnp";
     fetch = {
       type = "git";