Add Jest tests to the lint job

Change-Id: If0d63bc11f264e6e7287afdd0940d0f3b4ac1cf7
diff --git a/.zuul.yaml b/.zuul.yaml
index cf9c651..6965d34 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -11,6 +11,7 @@
     parent: web-ext-lint
     pre-run: playbooks/lint/pre.yaml
     run: playbooks/lint/run.yaml
+    post-run: playbooks/lint/post.yaml
     irrelevant-files:
       - ".github/.*"
       - "docs/.*"