feat(internal/kokoro): add ability to regen all DocFX YAML (#3191)
feat(internal/kokoro): add ability to regen all DocFX YAML (#3191)

Co-authored-by: Cody Oss <4f8e09b568d6600469c962b5159390a088c398ff@users.noreply.github.com>
googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go