Increase database pool size from 5 to 6

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1361 introduces a Rake task into GitLab EE that opens 6 database connections in parallel. This breaks with the existing GDK configuration, which only permits 5 in parallel.

The pool size in production is 25, so this seems like an unnecessary restriction. Increasing the number to 6 allows the rake task to complete successfully.

/cc @rspeicher

assigned to @grzesiek

@nick.thomas Looks good to me! Please enable CI/CD in your fork settings.

merged

Ach, I did wonder! Done.