date: fails to diagnose invalid input

date: fails to diagnose invalid input

date -d "$(printf '\xb0')" would print 00:00:00 with today's date
rather than diagnosing the invalid input.  Now it reports this:
date: invalid date '\260'
* gnulib: Update submodule to latest for fixed parse-datetime.y.
* tests/misc/date [invalid-high-bit-set]: New test.
* NEWS (Bug fixes): Mention it.
* bootstrap, tests/init.sh: Also update to latest.
Reported by Peter Evans in http://bugs.gnu.org/11843