s/owners/owner

The actual flag name is `owner`.

Author: cflewis

docs/book/quick_start.md

@@ -57,7 +57,7 @@ export PATH=$PATH:/usr/local/kubebuilder/bin
 Initialize the project directory.
 
 ```bash
-kubebuilder init --domain k8s.io --license apache2 --owners "The Kubernetes Authors"
+kubebuilder init --domain k8s.io --license apache2 --owner "The Kubernetes Authors"
 ```
 {% endmethod %}