Add zuul-results-summary plugin to check pipeline

Change-Id: I67ce5b8a6993e2e9f2b3db161eaeb9818691abc0

zuul.d/projects.yaml

diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index 279b18a..c2fefbd 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -307,3 +307,9 @@
     check:
       jobs:
         - gerrit-plugin-build
+
+- project:
+    name: plugins/zuul-results-summary
+    check:
+      jobs:
+        - gerrit-plugin-build