Action wheel builds do not happen when a tag is pushed.

This turned up when building wheels for v2.0.0b1, I needed to trigger them manually. I assume this is because push: has been removed from .github/workflows/wheels.yml.

Another potential problem is that the commit has both a tag and [wheel build]. I also wonder why only use the first line of the commit when looking for [wheel build]. I note the git log -1 --grep '\[wheel build\]' will also find the directive.