Update supported PostgreSQL versions in build workflow

Author: m3hm3t

.github/workflows/build-package-test.yml

@@ -44,12 +44,10 @@ jobs:
           - almalinux,8
           - almalinux,9
         POSTGRES_VERSION:
-          - 12
-          - 13
-          - 14
           - 15
           - 16
           - 17
+          - 18
         include:
           - TARGET_PLATFORM: debian,bullseye
           - TARGET_PLATFORM: debian,bookworm