Replace git pull command

Old version is no longer allowed

Author: briantoby

install/gitstrap.py

@@ -352,7 +352,8 @@ def update(self, op_code, cur_count, max_count=None, message=''):
                     logmsg(msg)
                     print(msg)
                 if not forceupdate: raise UserWarning(msg)            
-            g2repo.remotes.origin.pull(f'--depth={depth}')
+            #g2repo.remotes.origin.pull(f'--depth={depth}')  # replaced with following, as recommended by copilot
+            g2repo.git.pull('origin', depth=depth)
             return True
         elif os.listdir(repo_path):
             msg = f'directory {repo_path} is not empty and is not used by git'