Build avatars-gravatar plugin on stable-3.3

Change-Id: Icae79587e78cac25300f7cfc6f5345aafe810c5b
diff --git a/jenkins/gerrit-bazel-plugin-avatars-gravatar.yaml b/jenkins/gerrit-bazel-plugin-avatars-gravatar.yaml
index aa4a325..d3e3908 100644
--- a/jenkins/gerrit-bazel-plugin-avatars-gravatar.yaml
+++ b/jenkins/gerrit-bazel-plugin-avatars-gravatar.yaml
@@ -5,10 +5,11 @@
           branch:
             - master
           gerrit-branch:
-            - master
+            - stable-3.3
             - stable-3.2
             - stable-3.1
       - 'plugin-{name}-bazel-{branch}':
           branch:
+            - master
             - stable-3.0
             - stable-2.16