fixes(#827): allow plugins to extend all command groups#834

Merged

knative-prow-robot merged 3 commits intoknative:masterfrom maximilien:issue827

Jun 1, 2020

+124-42

Commits on May 13, 2020

* allow plugins to extends all comamnd groups, e.g., kn-service-blah is OK
maximilien
committed

Commits on May 28, 2020