feat!: Add Password Validation Policy to Postgres Module

[cleibl]

This PR adds support for the settings.password_validation_policy block in the PostgreSQL Module (https://cloud.google.com/sql/docs/postgres/built-in-authentication#instance_password_policies)

The Password Validation Policy is added as a dynamic block in the PostgreSQL module and is set to null by default to avoid conflicts with other modules.

I've added the password_validation_policy block (and related tests) to the postgres-public-iam example.

Integration Tests and Linting were performed and passed locally.

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[apeabody]

Thanks for the contribution @cleibl! A few quick items:

• Should this also be set to true? https://github.com/cleibl/terraform-google-sql-db/blob/master/modules/postgresql/main.tf#L201
• It appears password_validation_policy is new in TPG 4.33.0, please bump 4.28.0 to 4.33.0 here: https://github.com/cleibl/terraform-google-sql-db/blob/master/modules/postgresql/versions.tf#L30

Thanks!

[bharathkkb]

LGTM after @apeabody's comments. It would also be good to add an upgrade guide and also expose this for mysql/mssql modules if supported.

[cleibl]

Thanks for the comments, issues should be resolved now.

I would love to get all modules but only have time to PR changes for the Postgres updates

[apeabody]

Thanks @cleibl! - My comments have been addressed.

Hi @bharathkkb - Does this need an update guide?

[bharathkkb]

@apeabody since this is a new var with a null default we should be good to go

[comment-bot-dev]

@cleibl
Thanks for the PR! 🚀
✅ Lint checks have passed.