Use kuberay/ray-operator@vX.Y.Z Go module

[astefanutti]

Until now, KubeRay has not been tagging Go modules in such a way a specific version can be consumed.

Once ray-project/kuberay#1546 is applied, we should move to using the tagged version.

It may have to be done in codeflare-common once tests are moved into this repository after #336 is merged.