[CI] Use personal access token for backport workflow [fixup #15372] #4

	# WARNING:
	# When extending this action, be aware that $GITHUB_TOKEN allows write access to
	# the GitHub repository. This means that it should not evaluate user input in a
	# way that allows code injection.

	name: Backport

	on:
	pull_request_target:
	types: [closed, labeled]

	permissions:
	contents: write # so it can comment
	pull-requests: write # so it can create pull requests

	jobs:
	backport:
	name: Backport Pull Request
	if: github.repository_owner == 'crystal-lang' && github.event.pull_request.merged == true && (github.event_name != 'labeled' \|\| startsWith('backport', github.event.label.name))
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	with:
	ref: ${{ github.event.pull_request.head.sha }}
	token: ${{ secrets.BACKPORT_ACTION_GITHUB_PAT }}

	- name: Create backport PR
	uses: korthout/backport-action@be567af183754f6a5d831ae90f648954763f17f5 # v3.1.0
	with:
	github_token: ${{ secrets.BACKPORT_ACTION_GITHUB_PAT }}
	# Config README: https://github.com/korthout/backport-action#backport-action
	copy_labels_pattern: '^(breaking-change\|security\|topic:.\|kind:.\|platform:.*)$'
	copy_milestone: true
	pull_description: \|-
	Automated backport of #${pull_number} to `${target_branch}`, triggered by a label.

Provide feedback