style: use import wrapper everywhere

Align with Google style guides and `import wrapper` as a module
rather than import symbols out of it.

Change-Id: Ifc6165974a242a1ce38bd09b1b4226dc0ba943d5
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/654817
Reviewed-by: Brian Gan <brgan@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

git_command.py

@@ -25,7 +25,7 @@ import git_trace2_event_log_base
 import platform_utils
 import repo_logging
 import repo_trace
-from wrapper import Wrapper
+import wrapper
 
 
 GIT = "git"
@@ -46,7 +46,7 @@ logger = repo_logging.RepoLogger(__file__)
 class _GitCall:
     @functools.lru_cache(maxsize=None)  # noqa: B019
     def version_tuple(self):
-        ret = Wrapper().ParseGitVersion()
+        ret = wrapper.Wrapper().ParseGitVersion()
         if ret is None:
             msg = "fatal: unable to detect git version"
             logger.error(msg)