package/postgresql: security bump version to 15.3
Release notes:
https://www.postgresql.org/about/news/postgresql-153-148-1311-1215-and-1120-released-2637/
Fixes CVE-2023-2454 & CVE-2023-2455.
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>