[git_cl] Use named fields for URL manipulation

Change-Id: I575b91f6b6e28ac58160e3c0fc59398df222b150
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5677608
Auto-Submit: Allen Li <ayatane@chromium.org>
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>
Commit-Queue: Allen Li <ayatane@chromium.org>
Commit-Queue: Yiwei Zhang <yiwzhang@google.com>

git_cl.py

@@ -3647,7 +3647,7 @@ def ConfigureGitRepoAuth() -> None:
     remote_url: str = Changelist().GetRemoteUrl()
     parts: urllib.parse.SplitResult = urllib.parse.urlsplit(remote_url)
     # https://chromium.googlesource.com/
-    base_url: str = urllib.parse.urlunsplit((parts[0], parts[1], '/', '', ''))
+    base_url: str = parts._replace(path='/', query='', fragment='').geturl()
 
     should_use_sso: bool = gerrit_util.ShouldUseSSO(gerrit_host)