CI: add sync CRD reference step

[tao12345666333]

What this PR does / why we need it:

Which issue this PR fixes

Fixes #35

Special notes for your reviewer:

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect significant changes

[pmalek]

Actually there's one caveat: this should only happen for releases that are marked as latest.

Otherwise, if we already released 2.1, we'll overwrite the CRDs with 2.0.7.

[tao12345666333]

Actually there's one caveat: this should only happen for releases that are marked as latest.

Yes, once #2642 is merged, will that mitigate this issue?

Or, I can add a check to see whether the latest has been set?

[pmalek]

Actually there's one caveat: this should only happen for releases that are marked as latest.

Yes, once #2642 is merged, will that mitigate this issue?

Or, I can add a check to see whether the latest has been set?

#2642 will only make sure that links are version aware. If the scenario I mentioned above happens, docs specific for 2.1 would get removed.