Python 3.12 support: now declared in pyproject.toml, and Python 3.12 is used to run tests as well
CSS build: instead of having to explicitly installing dependencies yourself, you can now run npm clean-install or npm install in src/sphinx_antsibull_ext/css before running ./build.sh.
npm clean-install
ornpm install
insrc/sphinx_antsibull_ext/css
before running./build.sh
.