Test against PostgreSQL 16. (#16351)

.ci/scripts/calculate_jobs.py

@@ -64,7 +64,7 @@ if not IS_PR:
         {
             "python-version": "3.11",
             "database": "postgres",
-            "postgres-version": "15",
+            "postgres-version": "16",
             "extras": "all",
         }
     )

changelog.d/16351.misc

@@ -0,0 +1 @@
+Test against PostgreSQL 16.