Add preview link comment to PRs #3

	---
	name: Preview Button

	# yamllint disable-line rule:truthy
	on:
	pull_request:
	workflow_dispatch:

	permissions: read-all

	concurrency:
	group: ${{ github.ref }}-${{ github.workflow }}
	cancel-in-progress: true

	jobs:
	button:
	runs-on: ubuntu-latest

	permissions:
	issues: write
	pull-requests: write

	steps:
	- name: Setup custom variables
	id: customvars
	run: \|
	( echo -n "BASE_URL="
	if [ -n "${{ vars.BASE_URL }}" ] ; then
	echo "${{ vars.BASE_URL }}"
	else
	echo "<a href='https://federalist-a2423046-fe43-4e75-a2ef-2651e5e123ca.sites.pages.cloud.gov/preview/gsa-tts/tts.gsa.gov/' target='_blank' rel='noopener' style='width: -moz-fit-content; width: fit-content; background: #005ea2; border: 0; border-radius: .25rem .25rem 0 0; cursor: pointer; display: inline-block; font-weight: 700; margin-right: .5rem; padding: .75rem 1.25rem; text-align: center; position: fixed; bottom: 0; right: 0; color: #fff; text-decoration: none; letter-spacing: .5px; z-index: 10'>Preview this branch</a>"
	fi

	echo -n "URL_PATH="
	if [ -n "${{ vars.URL_PATH }}" ] ; then
	echo "${{ vars.URL_PATH }}/"
	elif [ -n "${GITHUB_HEAD_REF:-}" ] ; then
	echo "${GITHUB_HEAD_REF}/"
	else
	echo "staging/"
	fi
	) >> "$GITHUB_OUTPUT"

	- name: Comment on pull request.
	uses: thollander/actions-comment-pull-request@fabd468d3a1a0b97feee5f6b9e499eab0dd903f6 # pin@v2.5.0
	with:
	GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
	message: "${{ steps.customvars.outputs.BASE_URL }}${{ steps.customvars.URL_PATH }}"
	comment_tag: button

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