postgres-operator fix: set password encryption default to scram-sha-256

According to the Postgres official documentation, md5 passwords is deprecated in favor of scram-sha-256 encryption.

The change in this PR updates the default encryption to the new postgres default.

Documentation link: https://www.postgresql.org/docs/18/auth-password.html

Warning: Support for MD5-encrypted passwords is deprecated and will be removed in a future release of PostgreSQL.

Oct 15 '25 13:10 kadaffy

Cannot start a pipeline due to:

No accountable user for this pipeline: no Zalando employee associated to this GitHub username

Click on pipeline status check Details link below for more information.

Oct 15 '25 13:10 zalando-robot

Cannot start a pipeline due to:

No accountable user for this pipeline: no Zalando employee associated to this GitHub username

Click on pipeline status check Details link below for more information.

Oct 16 '25 10:10 zalando-robot