docs: update with new cni abilities

This PR updates the docs for cni

Signed-off-by: Spencer Smith <robertspencersmith@gmail.com>

docs/website/content/v0.3/en/configuration/v1alpha1.md

@@ -363,7 +363,8 @@ Examples:
 
 ```yaml
 network:
-  cni: flannel
+  cni:
+    name: flannel
   dnsDomain: cluster.local
   podSubnets:
   - 10.244.0.0/16
@@ -829,12 +830,23 @@ extraArgs:
 #### cni
 
 The CNI used.
+Composed of "name" and "url".
+The "name" key only supports upstream bootkube options of "flannel" or "custom".
+URLs is only used if name is equal to "custom".
+URLs should point to a single yaml file that will get deployed.
+Empty struct or any other name will default to bootkube's flannel.
 
-Type: `string`
+Type: `CNIConfig`
 
-Valid Values:
+Examples:
 
-- `flannel`
+```yaml
+cni:
+  name: "custom"
+  urls:
+    - "https://www.mysweethttpserver.com/supersecretcni.yaml"
+
+```
 
 #### dnsDomain
 
@@ -879,6 +891,22 @@ serviceSubnets:
 
 ---
 
+### CNIConfig
+
+#### name
+
+Name of CNI to use.
+
+Type: `string`
+
+#### urls
+
+URLs containing manifests to apply for CNI.
+
+Type: `array`
+
+---
+
 ### Bond
 
 #### mode

pkg/config/types/v1alpha1/v1alpha1_types.go

@@ -194,7 +194,8 @@ type ClusterConfig struct {
 	//   examples:
 	//     - |
 	//       network:
-	//         cni: flannel
+	//         cni:
+	//           name: flannel
 	//         dnsDomain: cluster.local
 	//         podSubnets:
 	//         - 10.244.0.0/16