ubuntu.yaml: add Noble, Oracular, Plucky #240

	name: Commits
	on:
	- pull_request

	permissions:
	contents: read

	jobs:
	dco-check:
	permissions:
	pull-requests: read # for tim-actions/get-pr-commits to get list of commits from the PR
	name: Signed-off-by (DCO)
	runs-on: ubuntu-20.04
	steps:
	- name: Get PR Commits
	id: 'get-pr-commits'
	uses: tim-actions/get-pr-commits@master
	with:
	token: ${{ secrets.GITHUB_TOKEN }}

	- name: Check that all commits are signed-off
	uses: tim-actions/dco@master
	with:
	commits: ${{ steps.get-pr-commits.outputs.commits }}

	target-branch:
	permissions:
	contents: none
	name: Branch target
	runs-on: ubuntu-20.04
	steps:
	- name: Check branch target
	env:
	TARGET: ${{ github.event.pull_request.base.ref }}
	run: \|
	set -x
	[ "${TARGET}" = "main" ] && exit 0

	echo "Invalid branch target: ${TARGET}"
	exit 1

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