block merge of squash! or fixup! commits

[blairconrad]

A feature request. I'm often involved in workflows where responses to code review comments result in fixup or squash commits being added to the PR. These are subsequently used with an --autosquash rebase flag and auto-squashed. Or fixed up.

(I assume you're familiar with this, but if not, a nice introduction can be had at George Brocklehurst's Auto-squashing Git Commits.)

The presence of these commits strongly indicates that work is still in progress. Could wip-bot block them as well?

[blairconrad]

I'd be willing to work on the feature, if it's deemed useful, but probably not until early April.

[gr2m]

closing in favor of #96 – would love your input there!