build but not publish when not in main branch

.drone.yml

@@ -13,6 +13,26 @@ steps:
     tags: latest
   when:
     branch:
-    - main
+      include:
+      - main
     event:
-    - push
+      include:
+      - push
+
+- name: docker-build
+  image: plugins/docker
+  settings:
+    username:
+      from_secret: DOCKER_USERNAME
+    password:
+      from_secret: DOCKER_PASSWORD
+    repo: aaronriedel/php-apache-mysql
+    tags: latest
+    dry_run: true
+  when:
+    branch:
+      exclude:
+      - main
+    event:
+      exclude:
+      - push