github.head_ref is only defined for pull_request event, so only those
will be grouped, the rest will fallback to unique run_id, so we neither
cancel them or serialize.
Not sure if this is particularly useful, but we might as well generate
these as well. Also use the docutils wrapper since that's what the meson
build does.
Copy and pasted from commit msg lint obviously, but I forgot to rename
it. Oops. Capitalize the name field while I'm at it (seems like all the
other workflows do it too).
Kacper Michajłow
Dudemanguy