Add healthcheck dependency to multi-site build

The multi-site plugin depends from the healthcheck because
of x-plugind dependency between pull-replication and healthcheck
API.

Change-Id: I24cb24a2b5646e86d49deb1c4e01cc509181f462
diff --git a/jenkins/gerrit-bazel-plugin-multi-site.yaml b/jenkins/gerrit-bazel-plugin-multi-site.yaml
index f77a18a..e80b0ef 100644
--- a/jenkins/gerrit-bazel-plugin-multi-site.yaml
+++ b/jenkins/gerrit-bazel-plugin-multi-site.yaml
@@ -2,7 +2,7 @@
     name: multi-site
     jobs:
       - 'plugin-{name}-bazel-{branch}':
-          extra-plugins: 'pull-replication'
+          extra-plugins: 'pull-replication healthcheck'
           extra-modules: 'events-broker global-refdb'
           branch:
             - master