Try not to deploy to the maven repo simply when a PR is open.

.drone.yml

@@ -20,7 +20,9 @@ steps:
         from_secret: repo-token
     commands:
       - mvn -s maven-settings.xml deploy -DskipTests=true
-    when:
+    trigger:
       branch:
-        include:
         - master
+      event:
+        exclude:
+        - pull_request