Move to latest libgit2 with PR #6706 merged

With libgit2/libgit2#6706 merged in we can now
use libgit2 from master. Small changes were needed.

This is needed in order to have stable hashes for e2e tests.

Previously we needed to use a patched version from:
https://github.com/u-quark/libgit2/commits/gg

flake.nix

@@ -8,7 +8,7 @@
       flake = false;
     };
     libgit2 = {
-      url = "github:u-quark/libgit2?ref=gg";
+      url = "github:libgit2/libgit2?ref=503b66cf";
       flake = false;
     };
     vty = {

src/GG/Repo/Commit.hs

@@ -76,7 +76,7 @@ getSignature commitContent program keyM = do
 createCommit :: G.Repository -> G.Signature -> String -> G.Tree -> [G.Commit] -> IO CreateCommitResult
 createCommit repo author message tree parents = do
   signConfig <- getSignConfig repo
-  committer <- G.signatureDefaultCommitter repo
+  (_author, committer) <- G.signatureDefaultFromEnv repo
   commitContent <- G.commitCreateBuffer repo author committer "UTF-8" message tree parents
   signatureME <-
     case signConfig of

src/Libgit2/Signature.chs

@@ -20,8 +20,7 @@ module Libgit2.Signature
   , signatureName
   , signatureEmail
   , signatureWhen
-  , signatureDefaultAuthor
-  , signatureDefaultCommitter
+  , signatureDefaultFromEnv
   ) where
 
 {#import Libgit2.Types#}
@@ -53,6 +52,4 @@ signatureWhen (Signature fp) =
     pure $ gitToLocalTime time offset
   )
 
-{#fun signature_default_author as signatureDefaultAuthor { alloca- `Signature' peekNewSignature*, `Repository' } -> `Int' checkReturnCode*-#}
-
-{#fun signature_default_committer as signatureDefaultCommitter { alloca- `Signature' peekNewSignature*, `Repository' } -> `Int' checkReturnCode*-#}
+{#fun signature_default_from_env as signatureDefaultFromEnv { alloca- `Signature' peekNewSignature*, alloca- `Signature' peekNewSignature*, `Repository' } -> `Int' checkReturnCode*-#}