codegen CI check can fail on release branches

[skriss]

Hmm, codegen failing because it's trying to pull Contour's main CRD YAML (which has changed). It should be looking at 1.18 YAML (which hasn't changed). Can ignore for now and follow up with a fix, I think.

Originally posted by @skriss in #431 (comment)

[skriss]

On release branches, https://github.com/projectcontour/contour-operator/blob/main/Makefile#L147-L151 has NEW_VERSION set to main, so it's pulling the main version of projectcontour/contour's CRD YAML instead of the release-branch-relevant version.