Devfile Registry Operator should be updated to support Go 1.21

[michael-valdron]

Which area is this issue related to?

/kind task

/area registry

Issue Description

Update devfile/registry-operator Go modules to use Go 1.21 with bumps to use k8s api v0.29.2.

Acceptance Critera

• Update to Go 1.21
• Bump dependencies including k8s api to v0.29.2
• Bump OpenShift version
• Do code refactoring where needed

[thepetk]

Opened 2 PRs:

• Registry Operator: Update go version to 1.21 registry-operator#91
• Openshift Release: chore: upgrade registry-operator tests to ocp 4.15 openshift/release#53498