Switch default reverse-proxy to Traefik, force reverse-proxy choice on existing users

roles/custom/matrix-base/defaults/main.yml

@@ -319,7 +319,7 @@ matrix_homeserver_app_service_config_files_auto: []
 #     - no nginx configuration will be dumped in /matrix/nginx/conf.d
 #     - no port exposure will be done for any of the container services
 #     - it's up to you to expose the ports you want, etc.
-matrix_playbook_reverse_proxy_type: playbook-managed-nginx
+matrix_playbook_reverse_proxy_type: ''
 
 matrix_playbook_service_host_bind_interface_prefix: "{{ '' if matrix_playbook_reverse_proxy_type not in ['other-nginx-non-container', 'other-on-same-host', 'other-on-another-host'] else ('0.0.0.0:' if matrix_playbook_reverse_proxy_type == 'other-on-another-host' else '127.0.0.1:') }}"
 

roles/custom/matrix-base/tasks/validate_config.yml

@@ -54,6 +54,14 @@
     msg: "Detected that variable matrix_architecture {{ matrix_architecture }} appears to be set incorrectly. See docs/alternative-architectures.md. Server appears to be {{ ansible_architecture }}."
   when: matrix_architecture not in ['amd64', 'arm32', 'arm64']
 
+- name: Fail if matrix_playbook_reverse_proxy_type is set incorrectly
+  ansible.builtin.fail:
+    msg: |
+      You have not explicitly specified the type of reverse-proxy you'd like to use (with a `matrix_playbook_reverse_proxy_type` variable in your configuration).
+      The playbook used to default to nginx (matrix-nginx-proxy), but things are changing with Traefik being the new default reverse-proxy.
+      Learn more here: https://github.com/spantaleev/matrix-docker-ansible-deploy/blob/master/CHANGELOG.md#traefik-is-the-default-reverse-proxy-now
+  when: matrix_playbook_reverse_proxy_type == ''
+
 - name: Fail if matrix_playbook_reverse_proxy_type is set incorrectly
   ansible.builtin.fail:
     msg: "Detected that variable matrix_playbook_reverse_proxy_type (current value: `{{ matrix_playbook_reverse_proxy_type }}`) appears to be set incorrectly. See roles/custom/matrix-base/defaults/main.yml for valid choices."