For minimal stuff, I just have a pre-commit hook that runs

    pandoc -s README.md -o index.html

I've done the xlst thing as well, but to generate markdown instead of HTML from Zotero export XML as the input. https://github.com/captn3m0/boardgame-research. But again, I throw the make command into a pre-commit because I want the README to be updated in the same commit.