misc/gnuls: Update to 9.1

ChangeLog: https://git.savannah.gnu.org/cgit/coreutils.git/tree/NEWS?h=v9.1

While here, add USES=localbase and pet linters

PR: 265910
Reported by: gaod@hychen.org
Approved by: bmc@clapper.org (maintainer, timeout > 2 weeks)