Add libpq-devel to UBI image

What does this MR do and why?

The Debian images add libpq-dev to support the pg gem, so we need this in UBI as well.

This came out of gitlab!144500 (merged).

Checklist

• (If applicable) Add patches if required for upgrading Ruby version in https://gitlab.com/gitlab-org/gitlab-build-images/-/tree/master/patches/ruby.