Lint

Add type-hints to `setup.py` and `imapclient/config.py`. Also use `argparse.Namespace` instead of `Bunch` #99

	name: Lint

	# If a pull-request is pushed then cancel all previously running jobs related
	# to that pull-request
	concurrency:
	group: ${{ github.workflow }}-${{ github.event.pull_request.number \|\| github.sha }}
	cancel-in-progress: true

	on:
	push:
	branches:
	- master
	pull_request:
	branches:
	- master

	env:
	PY_COLORS: 1

	jobs:
	lint:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	with:
	fetch-depth: 0
	- uses: actions/setup-python@v3
	- run: pip install --upgrade tox
	- name: Run black code formatter (https://black.readthedocs.io/en/stable/)
	run: tox -e black -- --check
	- name: Run isort import order checker (https://pycqa.github.io/isort/)
	run: tox -e isort -- --check
	- name: Run flake8 (https://flake8.pycqa.org/en/latest/)
	run: tox -e flake8
	- name: Run pylint Python code static checker (https://github.com/PyCQA/pylint)
	run: tox -e pylint

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