build: update posgres to 16

[paulschreiber]

Description

To upgrade your local development environment
With Postgres 14: ensure your backend Docker container is running (make run).
Back up your database:

CONTAINER_ID=`docker ps | grep postgis | cut -c 1-12`
docker exec -it  ${CONTAINER_ID} pg_dumpall -U postgres > terraso.sql

Delete the data directory:

docker compose -f docker-compose.dev.yml down
docker volume rm backend_postgresql_data

With Postgres 16: ensure your backend Docker container is running (make run).
Restore the data:

CONTAINER_ID=`docker ps | grep postgis | cut -c 1-12`
cat terraso.sql| docker exec -i ${CONTAINER_ID} psql -U postgres

[knipec]

Chatted with Paul, the context here is that Render made postgres 16 available so we're updating it. I tested this locally with the branch and the steps in the description and it looks good. FYI @shrouxm and @tm-ruxandra you'll want to run the steps once this gets merged