This update for postgresql18 fixes the following issue:
Update to version 18.3 (bsc#1258754).
Regression fixes:
- the substring() function raises an error 'invalid byte sequence for encoding' on non-ASCII text values if the
source of that value is a database column (caused by CVE-2026-2006 fix).
- a standby may halt and return an error 'could not access status of transaction'.