Build metrics-reporter-graphite against stable-1{2,3,4}

metrics-reporter-graphite plugin master branch has been migrated to
bazelmod with change Iad40d41a, so it is no longer compatibile with
Gerrit stable-3.12. stable-3.13 and stable-3.14.

Change-Id: I34c28fc5b4d5a9a640b4eed50343055223a4068a

jenkins/gerrit-bazel-plugin-metrics-reporter-graphite.yaml

diff --git a/jenkins/gerrit-bazel-plugin-metrics-reporter-graphite.yaml b/jenkins/gerrit-bazel-plugin-metrics-reporter-graphite.yaml
index 6ac0443..39471bb 100644
--- a/jenkins/gerrit-bazel-plugin-metrics-reporter-graphite.yaml
+++ b/jenkins/gerrit-bazel-plugin-metrics-reporter-graphite.yaml
@@ -4,3 +4,6 @@
       - 'plugin-{name}-bazel-{branch}':
           branch:
             - master
+            - stable-3.14
+            - stable-3.13
+            - stable-3.12