refactor: fix dangerous default argument (#22)

Do not use a mutable like `list` or `dictionary` as a default value to an argument. Python’s default arguments are evaluated once when the function is defined. Using a mutable default argument and mutating it will mutate that object for all future calls to the function as well.

Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>

src/plugins/nonebot_plugin_addFriend/configUtil.py

@@ -32,7 +32,9 @@ def check_dict_key_bot_id(config: dict, requestorDict: dict, numDict: dict, bot:
     # return True
 
 
-def readData(path, content={}, update=0) -> dict:
+def readData(path, content=None, update=0) -> dict:
+    if content is None:
+        content = {}
     if not exists(path):
         with open(path, "w", encoding="utf-8") as fp:
             json.dump(content, fp, ensure_ascii=False)