Fix Gitlab for nightly CI (FIPS issue)

Package Merge Request

Package Changes

Updates the init args for the postgres subchart so that the gitlab user is setup with scram-sha-256 encryption.

Package MR

https://repo1.dso.mil/platform-one/big-bang/apps/developer-tools/gitlab/-/merge_requests/137

For Issue

Closes https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/1200