fix: Update Ruby, Docker and fixes appsec check

Bumps Ruby and Docker. This should also resolve this MR: !104 (closed)

Also, it fixes appsec:

The appsec report artifcat is not returning the 'remediations' key, which is breaking the appsec_container_scanning job and blocking MRs.

Therefore this is fetching the :remediations key instead of accessing it directly so that it does not fail like calling concat(nil)

Here is a failing job that I've debugged and printed the output of the artifact to identify that this key wasn't present: https://gitlab.com/gitlab-org/cluster-integration/auto-build-image/-/jobs/2845549234#L58