Postgres version 16 support

[gabrielelucci]

I successfully restored a backup using docker.io/eeshugerman/postgres-backup-s3:15 on a container running docker.io/library/postgres:16-alpine, so I think it just works? Having official confirmation with a properly tagged image would be great!

[petre-c]

Restored, maybe, but when trying to back-up I receive:

pg_dump: error: aborting because of server version mismatch
pg_dump: detail: server version: 16.1 (Debian 16.1-1.pgdg120+1); pg_dump version: 15.3

[petre-c]

#39

[gabrielelucci]

Welp, you made me realize I've not been doing backups for two weeks! Luckily, I only updated one project, and it looks like the merge request is ready.

[eeshugerman]

Done! #39