Add menuextender plugin to the checks pipeline

Change-Id: I6c864dcffa679422d3df119376e938999b37de29
diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index a6f5da6..1fcb46e 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -165,6 +165,12 @@
         - gerrit-plugin-build
 
 - project:
+    name: plugins/menuextender
+    check:
+      jobs:
+        - gerrit-plugin-build
+
+- project:
     name: plugins/messageoftheday
     check:
       jobs: