Add with_grant_option to postgresql_default_privileges

[stawii]

This option exists in postgresql_grant but was missing in postgresql_default_privileges.
It is required to setup many things including Vault PostgreSQL Database Secrets Engine.

[cyrilgdn]

@stawii Thanks for the patch 👍

Could you add this new field in one of the test so it asserts that the SQL is valid please?

[stawii]

Sorry for late reply. There is no test in resource_postgresql_grant that I can take as an example.
I guess adding those tests might be another issue and out of scope of this PR ;)

[cyrilgdn]

@stawii You can simply add the flag (to true) in this test and check the attribute here, even if will not assert that use has the grant option, it'll cover the code and assert the query is valid.

[cyrilgdn]

I'll add the test.