Upgrade Version App rails gems to stay in line with security scanning

Problem

Security scanning found ~ 40 critical / high severity security problems in the version app dependencies see https://gitlab.com/gitlab-org/gitlab-services/version.gitlab.com/-/issues/26, most are due to outdated gems.

Desired Outcome

Dependency scanning no longer finds any critical / high severity security problems.

Proposed solution

Update all offending dependencies, see https://gitlab.com/gitlab-org/gitlab-services/version.gitlab.com/-/security/vulnerability_report/?activity=STILL_DETECTED

Status as of 23.10.2023:

Next steps (if any)

We'll tackle adding renovate bot separately in #28 (closed), to keep dependencies up to date from now on.