Remove workaround for GH pages publish step

[wolverian]

agda-template/.github/workflows/github-pages.yml

Lines 20 to 25 in 783ccf5

	- name: Copy HTML so the next step can read it
	run: cp -vHR result html
	- name: GitHub Pages
	uses: crazy-max/ghaction-github-pages@v2.5.0
	with:
	build_dir: html

This should not be needed anymore: crazy-max/ghaction-github-pages#155 (comment)