fix: fill head commit in payload

Author: wolfogre

Diff for: services/mirror/mirror_pull.go

@@ -499,6 +499,13 @@ func SyncPullMirror(ctx context.Context, repoID int64) bool {
 			theCommits.Commits = theCommits.Commits[:setting.UI.FeedMaxCommitNum]
 		}
 
+		if newCommit, err := gitRepo.GetCommit(newCommitID); err != nil {
+			log.Error("SyncMirrors [repo: %-v]: unable to get GetCommit [%s]: %v", m.Repo, newCommitID, err)
+			continue
+		} else {
+			theCommits.HeadCommit = repo_module.CommitToPushCommit(newCommit)
+		}
+
 		theCommits.CompareURL = m.Repo.ComposeCompareURL(oldCommitID, newCommitID)
 
 		notification.NotifySyncPushCommits(ctx, m.Repo.MustOwner(ctx), m.Repo, &repo_module.PushUpdateOptions{