Add markup to Libpng.xml #1903

	on:
	pull_request:
	workflow_dispatch:
	push:
	branches-ignore: main
	jobs:
	validate_schema:
	name: Validate schema
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- name: Set up Python 3.10
	uses: actions/setup-python@v5
	with:
	python-version: "3.10"
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install -r requirements.txt
	- name: Validate schema
	run: \|
	python validate-schema.py
	validate_canonical_match:
	name: Validate canonical match
	runs-on: ubuntu-latest
	steps:
	- uses: actions/setup-java@v1
	with:
	java-version: '11'
	- uses: actions/checkout@v4
	- name: Fetch changes for git diff
	id: fetchdiff
	run: \|
	if [ $GITHUB_BASE_REF ]; then
	# Pull Request
	git fetch origin $GITHUB_BASE_REF --depth=1
	export BASE_REF=origin/$GITHUB_BASE_REF
	elif [ ${{ github.event.before }} != 0000000000000000000000000000000000000000 ]; then
	# Push
	git fetch origin ${{ github.event.before }} --depth=1
	export BASE_REF=${{ github.event.before }}
	else
	# This is the first commit in the branch - use the first commit
	export BASE_REF=$(git log -n 1 --pretty=format:"%H")
	fi
	echo "::set-output name=BASE_REF::$BASE_REF"
	- run: echo ${{steps.fetchdiff.outputs.BASE_REF}}
	- name: Validate canonical match
	run: make validate-canonical-match
	env:
	INPUT_BASE_REF: ${{ steps.fetchdiff.outputs.BASE_REF }}

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