book: fix typo in curl command
fix typo in curl command
@@ -31,7 +31,7 @@ Install [kubebuilder](https://sigs.k8s.io/kubebuilder):
```bash
# download kubebuilder and install locally.
-curl -L -o kubebuilder https://go.kubebuilder.io/dl/latest/$\(go env GOOS\)/$\(go env GOARCH\)
+curl -L -o kubebuilder https://go.kubebuilder.io/dl/latest/$(go env GOOS)/$(go env GOARCH)
chmod +x kubebuilder && mv kubebuilder /usr/local/bin/
```
