chore Upgrade to Postgres 16.1 (test+prod)

Dev is already ahead of the game by being on 16.2:

```
; kubectl --context iam-dev exec -it dino-park-packs-pg-deployment-56b7dd5b49-gd688 -- postgres --version
postgres (PostgreSQL) 16.2 (Debian 16.2-1.pgdg120+2)
```

@gcoxmoz pointed out

    pg_upgrade supports upgrades from 9.2.X and later to the current major release of PostgreSQL, including snapshot and beta releases.

See: https://www.postgresql.org/docs/16/pgupgrade.html

Jira: IAM-1502

terraform/prod/db.tf

@@ -4,7 +4,7 @@ resource "aws_db_instance" "dino_park_packs_db" {
   max_allocated_storage       = 100
   storage_type                = "gp2"
   engine                      = "postgres"
-  engine_version              = "11.22"
+  engine_version              = "16.1"
   instance_class              = "db.t3.micro"
   allow_major_version_upgrade = true
   username                    = "dinopark"

terraform/test/db.tf

@@ -4,7 +4,7 @@ resource "aws_db_instance" "dino_park_packs_db" {
   max_allocated_storage               = 100
   storage_type                        = "gp2"
   engine                              = "postgres"
-  engine_version                      = "11.22"
+  engine_version                      = "16.1"
   instance_class                      = "db.t3.micro"
   allow_major_version_upgrade         = true
   username                            = "dinopark"