more pkg examples

pkg/README.md

@@ -32,3 +32,5 @@ Examples:
 * https://github.com/sourcegraph/sourcegraph/tree/master/pkg
 * https://github.com/sosedoff/pgweb/tree/master/pkg
 * https://github.com/GoogleContainerTools/skaffold/tree/master/pkg
+* https://github.com/knative/serving/tree/master/pkg
+