Security announcement: https://groups.google.com/g/golang-announce/c/xtuG5faxtaU

Part of https://gitlab.com/groups/gitlab-org/-/epics/8843

go 1.17 is no longer receiving security updates. Update to go 1.18 in
preparation for upgrading.

Part of https://gitlab.com/groups/gitlab-org/-/epics/8843

We don't need Ruby 2.7.4 cluttering our GDK when everything else has
been upgraded to 2.7.5.

Part of https://gitlab.com/groups/gitlab-org/-/epics/7111