upload: Add rev to rootRepo push option

Bug: b/401147338
Change-Id: Iac19af5aadd250538702920d9beaeef9250c78fe
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/478801
Tested-by: Gavin Mak <gavinmak@google.com>
Reviewed-by: Scott Lee <ddoman@google.com>

git_superproject.py

@@ -178,7 +178,8 @@ class Superproject:
             if netloc := parsed_url.netloc:
                 parts = netloc.split("-review", 1)
                 host = parts[0]
-                return f"{host}/{self.name}"
+                rev = GitRefs(self._work_git).get("HEAD")
+                return f"{host}/{self.name}@{rev}"
         return None
 
     def _LogMessage(self, fmt, *inputs):