Add releaser CI scripts #595

# to view logs

	name: Python package

	on: [push, pull_request]

	jobs:
	build:

	runs-on: ubuntu-latest
	strategy:
	fail-fast: false
	max-parallel: 4
	matrix:
	python-version: [3.8, 3.9, "3.10", "3.11"]

	steps:
	- uses: actions/checkout@v1
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v1
	with:
	python-version: ${{ matrix.python-version }}
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	- name: Lint with flake8
	run: \|
	pip install flake8
	# stop the build if there are Python syntax errors or undefined names
	flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
	# exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
	flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
	- name: Test with pytest
	run: \|
	python -m pip install ".[test]"
	pytest -v
	- name: HTML validator
	run: \|
	python -m pip install html5validator
	voila --template=gridstack --no-browser &
	sleep 2
	mkdir _crawled
	curl http://127.0.0.1:8866/voila/render/tests/nb.ipynb > _crawled/nb.html
	html5validator \|\| true

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