pluginupdate.py: print script duration

to help track the plugin speed across time

maintainers/scripts/pluginupdate.py

@@ -788,7 +788,10 @@ def update_plugins(editor: Editor, args):
     fetch_config = FetchConfig(args.proc, args.github_token)
     update = editor.get_update(args.input_file, args.outfile, fetch_config)
 
+    start_time = time.time()
     redirects = update()
+    duration = time.time() - start_time
+    print(f"The plugin update took {duration}s.")
     editor.rewrite_input(fetch_config, args.input_file, editor.deprecated, redirects)
 
     autocommit = not args.no_commit