Add errors docstrings

Fix support of Python 3.8

Update README.md

Add docs links

Bump version

Add Python 3.11 to lib-test

Bump version in pyproject.toml

Merge pull request #3 from LulzLoL231/1-webhook-support

Add webhook support

Add blank line to dev requirements

Make setup file, rewrite requirements, rewrite README.

v1.2: Use 1 ClientSession for all requests.