Add server-config plugin to the checks pipeline

Change-Id: I3c521bd045cd0bd6ad60afbc365e0f58e5d9b56e

zuul.d/projects.yaml

diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index c2fefbd..ceb258f 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -279,6 +279,12 @@
         - gerrit-plugin-build
 
 - project:
+    name: plugins/server-config
+    check:
+      jobs:
+        - gerrit-plugin-build
+
+- project:
     name: plugins/serviceuser
     check:
       jobs: