Build healthcheck stable-3.3 branch

Feature: Issue 13712
Change-Id: I3ebe6a5c1b782d4436080d5c7eaba69a59b6bde9
diff --git a/jenkins/gerrit-bazel-plugin-healthcheck.yaml b/jenkins/gerrit-bazel-plugin-healthcheck.yaml
index 6447a6a..87ded9c 100644
--- a/jenkins/gerrit-bazel-plugin-healthcheck.yaml
+++ b/jenkins/gerrit-bazel-plugin-healthcheck.yaml
@@ -4,6 +4,7 @@
       - 'plugin-{name}-bazel-{branch}':
           branch:
             - master
+            - stable-3.3
             - stable-3.2
             - stable-3.1
             - stable-3.0