dev-cmd/bump-formula-pr: support underscores in version

`Version.parse` converts underscores to dots so add this to bump which
allows us to enable autobump support in multiple formulae.

There is a small chance of false-positives in URL. There didn't seem to
be any in Homebrew/core, but can improve bump in future to either be
"smarter" than just gsub and/or to attempt multiple possible URLs.

Also always show failed resource bumps as checkbox. This allows showing
failure for non-PyPI resources when formula has mix of both.