This script is failing currently on
https://github.com/jesseduffield/lazygit/pull/3631 because that fork's
master branch is 300 commits behind our own, but the feature branch is
up to date.
The thing is, we don't actually need to involve the master branch. All
we care about is the feature branch's own commits, so this commit simply
fetches those commits and checks them.
Also check for squash! and amend! (these are all anchored to the beginning of
the subject), and WIP and DROPME for good measure (but only if they occur in the
first line, otherwise it wouldn't let me merge this very commit :)
My local git is not compiled with PCRE support, so using -E makes it easier for
me to test the script locally. And -E is good enough for the simple matching we
want to do here.
