Make GetCommitFileStatus list all files impacted by a merge commit

Enable APIs (such as 'api/v1/repos/{owner}/{repo}/git/commit/{sha1}') to correctly
list all files impacted by a commit (making it mirror GitHub API behaviour).
Previously would only return merge commit files if they where associated
with a conflict resolution.

Author: jasugun

modules/git/commit.go

@@ -500,7 +500,7 @@ func GetCommitFileStatus(ctx context.Context, repoPath, commitID string) (*Commi
 	}()
 
 	stderr := new(bytes.Buffer)
-	args := []string{"log", "--name-status", "-c", "--pretty=format:", "--parents", "--no-renames", "-z", "-1", commitID}
+	args := []string{"log", "--name-status", "-c", "--pretty=format:", "--parents", "--no-renames", "-m", "-z", "-1", commitID}
 
 	err := NewCommand(ctx, args...).Run(&RunOpts{
 		Dir:    repoPath,