require the PKGBUILD itself to be added to git
This makes pkgctl
fail more explicitly, when PKGBUILD is present but not under version control:
$ pkgctl release --repo extra
==> Releasing testrepository-issue-154 to extra
error: pathspec 'PKGBUILD' did not match any file(s) known to git
Did you forget to 'git add'?
==> ERROR: PKGBUILD is not under version control
Closes #154 (closed)
Closes #167 (closed)