DigitalOcean removed CoreOS as an available distro image, so replacing with RancherOS.
What does this MR do?
Replace CoreOS image with RancherOS image.
Why was this MR needed?
DigitalOcean removed coreos as an available image https://slugs.do-api.dev/, so jobs would fail if still trying to use coreos.
For example this issue was also raised at https://forum.gitlab.com/t/gitlab-runner-for-digitalocean-uses-coreos-stable-which-is-now-end-of-life/42995
I tested with RancherOS and it seems to work fine as a replacement.
Edited by Andrew Harvey