Add a CI check to make sure that pull requests are not missing make generate

[m1kola]

We need a check for PRs to make sure that we generate all the generated code and yamls as part of a PR.

[joelanford]

Just need to add manifests to this target's dependencies?

operator-controller/Makefile

Line 82 in fd7cfb5

verify: tidy fmt generate ## Verify the current code generation.

CI already runs make verify as part of the sanity workflow.

[m1kola]

@joelanford you are right we already have verify which runs git diff --exit-code and we can add manifests as a dependency.

However git diff --exit-code will only produce non-zero exit code if there is a diff in tracked files and it will miss cases when working copy is dirty due to new untracked files as result of code generation.

I think we need something like [[ -z "$(git status -s)" ]] instead.