codespell: Ignore .git

codespell: Ignore .git

Otherwise the first line of commit messages is checked,
because text is found in .git/logs/HEAD, but only on
autobuild and not in CI (which does a shallow clone),
and not the whole commit message either, which is inconsistent.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15503

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Thu Oct 26 23:27:29 UTC 2023 on atb-devel-224