Support for PostgresQL

[kettenbach-it]

Hi Benjamin,

I like your tool and will use it on my gke-k8s to backup my gcp-mysql server to gcs.
If you hadn't written the script, I probably would have had to....
I use postgresql on gcp in addition to mysql.

Would you accept a patch that adds support for Postgres?

Best regards
Volker

[kettenbach-it]

FYI: submitted first pull request implementing the DATE_PREFIX feature correctly:
#43

[kettenbach-it]

Someone already implemented something similar for Postgres:
https://github.com/diogopms/postgres-gcs-backup

I think I'll go with that