Build GDK images with go up to 1.21

What does this MR do and why?

Builds GDK e2e images with go 1.20 and 1.21 so we can run the e2e tests when those versions are used by GDK.

Checklist

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