fix linting issue

Author: wj-Mcat

src/wechaty/config.py

@@ -100,13 +100,13 @@ def cache_dir(self) -> str:
             str: the path of cache dir
         """
         return os.environ.get("CACHE_DIR", '.wechaty')
-    
+
     @property
     def ui_dir(self) -> str:
         """get the ui directory
 
         Returns:
-            str: the path of the ui dir 
+            str: the path of the ui dir
         """
         default_ui_dir = os.path.join(
             os.path.dirname(__file__),

src/wechaty/plugin.py

@@ -591,7 +591,7 @@ def add_plugin(self, plugin: Union[str, WechatyPlugin]) -> None:
                 log.warning('plugin : %s has exist', plugin.name)
                 return
             plugin_instance = plugin
-        
+
         # set the scheduler
         plugin.scheduler = self.scheduler
         self._plugins[plugin_instance.name] = plugin_instance