Add uncrustify check to github actions

Add uncrustify check to github actions

This adds checking if the code style is still clean github actions with the
exact version of uncrustify that is required and might also be helpful for
external commiters to get notified about code style problem when running
the Github actions on their own repository.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20220506132836.1318985-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg24300.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>