add matrix channel notification

.drone.yml

@@ -20,3 +20,13 @@ steps:
       - git clone https://gitea.rknet.org/ansible/ansible-later-policy.git ~/policy
       - git ls-files *[^LICENSE,.md] | xargs ansible-later -c ~/policy/config.ini
     depends_on: [ clone ]
+
+  - name: notify
+    image: plugins/matrix
+    settings:
+      homeserver: https://matrix.rknet.org
+      roomid: cicd:rknet.org
+      username:
+        from_secret: matrix_username
+      accesstoken:
+        from_secret: matrix_accesstoken