feat: add first class support for private github repos (#1271)

Signed-off-by: Devin Buhl <devin@buhl.casa>

bootstrap/templates/kubernetes/flux/config/cluster.yaml.j2

@@ -7,7 +7,7 @@ metadata:
 spec:
   interval: 30m
   url: "{{ flux.github.address }}"
-  {% if flux.github.address.startswith('ssh://') %}
+  {% if flux.github.private.enabled %}
   secretRef:
     name: github-deploy-key
   {% endif %}