Update book with kustomize go link

This updates the book with the kustomize go link and adds a brief block
on installing kustomize from that link.

docs/book/src/quick-start.md

@@ -9,9 +9,6 @@ This Quick Start guide will cover:
 
 ## Installation
 
-Install [kustomize](https://sigs.k8s.io/kustomize).
-
-
 Install [kubebuilder](https://sigs.k8s.io/kubebuilder):
 
 ```bash
@@ -27,6 +24,16 @@ sudo mv /tmp/kubebuilder/kubebuilder_2.0.0_${os}_${arch} /user/local/kubebuilder
 export PATH=$PATH:/usr/local/kubebuilder/bin
 ```
 
+Install [kustomize](https://sigs.k8s.io/kustomize):
+
+```bash
+os=$(go env GOOS)
+arch=$(go env GOARCH)
+
+# download kustomize to the kubebuilder assets folder
+curl -o /usr/local/kubebuilder/bin/kustomize -sL https://go.kubebuilder.io/dl/latest/${os}/${arch}
+```
+
 ## Create a Project
 
 Initialize a new project and Go module for your controllers: