* Added class `ChatMemberUpdated` to types
* Simplified `de_json` functions in `WebhookInfo` and `Update` classes (for overall more consistent code)
* changed `options_ids` to ´option_id` in class `PollAnswer`
* Added test for `ChatMemberUpdated` class in `test_types.py` and added the fields `my_chat_member` and `chat_member` to the `Update` class and its tests