Rename kubespray-defaults to kubespray_defaults

Role names in ansible collection should not contains hyphens.

playbooks/boilerplate.yml

@@ -42,5 +42,5 @@
   gather_facts: false
   environment: "{{ proxy_disable_env }}"
   roles:
-    - { role: kubespray-defaults }
+    - { role: kubespray_defaults }
     - { role: bastion-ssh-config, tags: ["localhost", "bastion"] }