gitmodules: remove .git suffix Bug: b/303296048 Change-Id: Ic15a88624fd3ffa0ec14cd1682e4385729f7c19f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5038232 Auto-Submit: Josip Sokcevic <sokcevic@chromium.org> Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: Yuxin Hu <yuxinhu@google.com>