Debian stable docker tag got updated to bullseye, stay on buster
What does this MR do?
Make sure to pin the debian version we use in our CI to buster. bullseye was released this weekend.
Why was this MR needed?
First job of master build is failing https://gitlab.com/gitlab-org/ci-cd/shared-runners/images/macstadium/orka/-/jobs/1507302010