Build ghs-metrics-collector plugin on stable-3.13

Change-Id: If5cbfdfdb4dce3449e45ecdfa217e563ef426005
diff --git a/jenkins/gerrit-bazel-plugin-ghs-metrics-collector.yaml b/jenkins/gerrit-bazel-plugin-ghs-metrics-collector.yaml
index 29e2943..cbc1a06 100644
--- a/jenkins/gerrit-bazel-plugin-ghs-metrics-collector.yaml
+++ b/jenkins/gerrit-bazel-plugin-ghs-metrics-collector.yaml
@@ -11,6 +11,7 @@
           branch:
             - master
           gerrit-branch:
+            - stable-3.13
             - stable-3.12
             - stable-3.11
             - stable-3.10