Add pre-commit #18

	name: 'flake'
	# https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#concurrency
	# https://docs.github.com/en/developers/webhooks-and-events/events/github-event-types#pullrequestevent
	# workflow name, PR number (empty on push), push ref (empty on PR)
	concurrency:
	group: ${{ github.workflow }}-${{ github.event.number }}-${{ github.event.ref }}
	cancel-in-progress: true
	on:
	push:
	branches:
	- '*'
	pull_request:
	branches:
	- '*'

	jobs:
	style:
	name: 'flake'
	runs-on: ubuntu-20.04
	steps:
	- uses: actions/checkout@v3
	- uses: actions/setup-python@v4
	with:
	python-version: '3.9'
	architecture: 'x64'
	- run: \|
	python -m pip install --upgrade pip setuptools wheel
	python -m pip install flake8
	name: 'Install dependencies'
	- uses: rbialon/flake8-annotations@v1
	name: 'Setup flake8 annotations'
	- run: make flake
	name: 'Run flake8'

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