Use latexmkrc to define file exts to clean up #36

	# While this action's image (https://github.com/xu-cheng/texlive-action,
	# ghcr.io/xu-cheng/texlive-full:latest) is "only" 2 GiB, as opposed to
	# texlive/texlive with a whopping 4 GiB (!!), it already fails when "apk add
	# make". Also using the image as is instead of the "action" (which just
	# shell-execs the string below "run" :)) fails when pulling it from ghcr.io. So
	# 4 GiB it is, then.

	##jobs:
	## pdf:
	## runs-on: ubuntu-latest
	##
	## steps:
	## - name: checkout
	## uses: actions/checkout@v2
	##
	## - name: build
	## uses: xu-cheng/texlive-action/full@master
	## with:
	## run: \|
	## apk update && apk add make && sh .github/scripts/build_pdf.sh built_pdfs


	name: Build and release PDF

	on: push

	jobs:
	pdf:
	runs-on: ubuntu-latest

	container:
	image: texlive/texlive

	steps:
	- name: checkout
	uses: actions/checkout@v2

	- name: build
	run: \|
	sh .github/scripts/build_pdf.sh built_pdfs

	# Upload artifact for each CI run. Not needed for release_if_tag! This
	# uses the output of steps.build .
	- name: upload artifact
	uses: actions/upload-artifact@master
	with:
	name: built_pdfs
	path: built_pdfs

	# Create a release and attach built_pdfs/*.pdf to that for easy download.
	- name: release_if_tag
	uses: softprops/action-gh-release@master
	if: startsWith(github.ref, 'refs/tags/')
	with:
	files: "built_pdfs/*"
	env:
	GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

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