maint: release process streamlining.
maint: release process streamlining.

* GNUmakefile (check-in-release): Don't switch back to master yet.
(release): Do it at the end!

Signed-off-by: Gary V. Vaughan <f9023000f29773649f3850298becb9544b5fd6a9@gnu.org>

GUI/lyaml,GUI/lyaml