Adding --dry-run flag #167

	name: publish

	on: [push]

	jobs:
	sphinx:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	with:
	fetch-depth: 0
	- name: Install Requirements
	run: \|
	pip3 install -r requirements.txt
	- name: Sphinx build
	run: \|
	sphinx-multiversion . build
	- name: Publish gh-pages
	if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
	run: \|
	cd build
	git init
	git config user.name "Key4hep bot"
	git config user.email "[email protected]"
	git remote add upstream https://vvolkl:${{ secrets.GITHUB_TOKEN }}@github.com/${GITHUB_REPOSITORY}.git

	touch .nojekyll
	git add .nojekyll
	git commit -m "Initial commit"
	git branch -m gh-pages
	touch .
	cp ../.github/aux/gh-pages-redirect.html index.html
	git add -A .
	git commit -m "Rebuild page at ${GITHUB_SHA}"
	git push -f upstream gh-pages:gh-pages

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