replace backport github action with mergify #4

	name: "Label PR"

	on:
	pull_request_target:
	types: [edited, opened, synchronize, reopened]

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

	permissions:
	contents: read
	pull-requests: write

	jobs:
	labels:
	runs-on: ubuntu-latest
	if: github.repository_owner == 'NixOS'
	steps:
	- uses: actions/labeler@v5
	with:
	repo-token: ${{ secrets.GITHUB_TOKEN }}
	sync-labels: false

Provide feedback