Config-client

**changelog**

- `python-dotenv` removed from CLI dependencies;
- `get_config_async` updated to get running loop, as recommended by [asyncio.get_event_loop docs](https://docs.python.org/3/library/asyncio-eventloop.html?highlight=asyncio%20get_event_loop#asyncio.get_event_loop).

**changelog**

- updated [docs](https://config-client.amenezes.net)
- `get_attribute` and `get_keys` are now **deprecated**
- `url` property **removed**
- Configuration files are now merged into the client to resolve the problem relative to use of json extension. So a simple way to test and saw how configuration will be available can be done using the config client CLI. For more info see the issue 18 and [docs](https://config-client.amenezes.net/docs/3.-command-line/)
- `get_config_async` available to retrieve configuration in async environments

**changelog**

- internal improvements
- use of the new attrs syntax

**changelog**

- fix issue 44, adjustment in parameters options for: oauth2 token, FlaskConfig and AioHttpConfig
- docs updated: https://config-client.amenezes.net

**changelog**
- added support for python 3.10

**changelog**

- fix issue 43
- config-cli client now show color output
- code refactored