Update the Ruby and gem version used in the release job
- Use the
ruby:2.6
base image for all jobs. - Install gems under
vendor
and cachevendor/ruby
. - Update
gem
in therelease
job. It's currently updated to 3.0.6, as can be seen in https://gitlab.com/gitlab-org/gitlab-qa/-/jobs/337006178.
Closes #431 (closed), #432 (closed).
Edited by George Koltsov