Don't test the build on promoted build event

.drone.yml

@@ -11,7 +11,12 @@ server:
 steps:
 - name: build
   commands:
-  -  make build
+  - make build
+
+trigger:
+  event:
+    exclude:
+      - promote
 
 ---
 
@@ -37,6 +42,6 @@ steps:
 
 trigger:
   event:
-  - promote
+    - promote
   target:
   - production