Add job to lint posts on push and PR #485

	name: Check accessibility of changed content

	on:
	pull_request:

	permissions:
	contents: read
	pull-requests: read

	concurrency:
	group: '${{ github.workflow }} @ ${{ github.event.pull_request.head.label \|\| github.head_ref \|\| github.ref }}'
	cancel-in-progress: true

	jobs:
	check-a11y-of-changed-content:
	name: Check accessibility of changed content
	runs-on: ubuntu-latest
	steps:
	- name: Checkout
	uses: actions/checkout@v4

	- name: Fetch gh-pages branch
	run: >-
	git fetch origin gh-pages
	&& git branch gh-pages origin/gh-pages;

	- name: Calculate URLs and output to JavaScript module
	run: >-
	chmod +x ./generate_pa11y_ci_urls_from_git_diff.sh
	&& ./generate_pa11y_ci_urls_from_git_diff.sh gh-pages
	>> ./pa11y-ci-urls.js;

	- name: Log contents of resulting JavaScript module
	run: cat ./pa11y-ci-urls.js;

	- name: Setup Ruby
	uses: ruby/setup-ruby@v1
	with:
	ruby-version: 2.3

	- name: Install gems
	run: bundle config path vendor/bundle && bundle install

	- name: Run the blog
	run: bundle exec jekyll serve &

	- name: Setup Node
	uses: actions/setup-node@v4
	with:
	node-version: 20.x
	cache: npm

	- name: Install NPM dependencies
	run: npm ci

	- name: Setup Chrome
	uses: browser-actions/setup-chrome@v1
	id: setup-chrome

	- name: Wait for blog to be running
	run: npx wait-on http://localhost:4000 --timeout 60000

	- name: Run pa11y-ci
	run: CHROMIUM_BIN=$(which chrome) npx pa11y-ci

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