mypy: ignore imports of python-telegram-bot

```
location_guessing_game_telegram_bot/__init__.py:27: error: Skipping analyzing 'telegram.ext': found module but no type hints or library stubs
location_guessing_game_telegram_bot/__init__.py:27: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
location_guessing_game_telegram_bot/__init__.py:27: error: Skipping analyzing 'telegram': found module but no type hints or library stubs
location_guessing_game_telegram_bot/__init__.py:28: error: Skipping analyzing 'telegram.update': found module but no type hints or library stubs
```

mypy.ini

@@ -0,0 +1,4 @@
+[mypy]
+[mypy-telegram.*]
+# no longer required in python-telegram-bot>=13 ?
+ignore_missing_imports = True