docker: updated template with DockerMachineTemplate default namespace

Cluster API now fails with namespace reference not found, if the DockerMachineTemplate
does not have a namespace set.

Partially-Fixes: #136

Author: ader1990

templates/docker/cluster-template-dualstack.yaml

@@ -39,6 +39,7 @@ spec:
       apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
       kind: DockerMachineTemplate
       name: ${CLUSTER_NAME}-control-plane
+      namespace: default
   spec:
     airGapped: true
     controlPlane:

templates/docker/cluster-template.yaml

@@ -37,6 +37,7 @@ spec:
       apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
       kind: DockerMachineTemplate
       name: ${CLUSTER_NAME}-control-plane
+      namespace: default
   spec:
     airGapped: true
     controlPlane: