fix: bump postgres version to 16

Co-authored-by: Thomas TACQUET <[email protected]>

Author: cyclimse

containers/vpc-metabase/main.tf

@@ -1,6 +1,6 @@
 locals {
   name                = "metabase-example"
-  db_postgres_version = "15"
+  db_postgres_version = "16"
   base_tags           = ["metabase", "vpc"]
 }