prow: lgtm plugin should check collaborators
We can no longer assume that assignees are safe to lgtm a PR. We should
actually check repo collaborators before actioning an lgtm event.
Bump all 0.26.x pinned bazel versions to 0.26.1
Add tag for bazel jobs that should have a tagged revision
Migrate service-catalog to kubernetes-sigs
Add cblecker to prow owners