Bump async from 2.20.0 to 2.21.0 #900

	# This workflow will build a middleman project with bundle

	name: Testing For PRs

	on: [ pull_request ]

	env:
	RUBYOPT: -W0 # needed to not print the warnings - makes the logs too big
	RUN_EXTERNAL_CHECKS: true

	jobs:
	build_and_push_to_preview:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- name: Set up Ruby
	uses: ruby/setup-ruby@v1
	with:
	ruby-version: 3.3
	bundler-cache: true # would run bundle install
	- name: Set up user in git config
	env:
	USER: "${{ secrets.GH_PREVIEW_WRITE_USER }}"
	run: \|
	git config --global user.name "${USER}"
	git config --global user.email "${USER}@github.com"
	- name: Run the build
	run: bundle exec rake build --verbose
	- name: Build failed
	if: ${{ failure() }}
	run: bundle exec middleman build --verbose
	- name: Push to preview
	run: \|
	export PR_NO=$(echo $GITHUB_REF \| awk 'BEGIN { FS = "/" } ; { print $3 }')
	git clone --depth=1 --branch=gh-pages "https://${USER}:${TOKEN}@github.com/gocd/pr-review.gocd.org" website
	rm -rf website/pr-${PR_NO}
	mv build website/pr-${PR_NO}
	cd website && git config core.filemode false && git add -A .
	git commit -m "Update website to ${PR_NO}" && git push
	env:
	USER: "${{ secrets.GH_PREVIEW_WRITE_USER }}"
	TOKEN: "${{ secrets.GH_PREVIEW_WRITE_USER_ACCESS_TOKEN }}"

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