Add a network definition to v1alpha6 e2e templates

This ensures an API transformation is required when upgrading.

Author: mdbooth

test/e2e/data/kustomize/v1alpha6/kustomization.yaml

@@ -6,3 +6,17 @@ components:
 - ../common-patches/cni
 - ../common-patches/containerd
 - ../common-patches/ccm
+
+patches:
+- target:
+    kind: OpenStackMachineTemplate
+  patch: |-
+    apiVersion: infrastructure.cluster.x-k8s.io/v1alpha6
+    kind: OpenStackMachineTemplate
+    metadata:
+      name: ignored
+    spec:
+      template:
+        spec:
+          networks:
+          - {}