diff --git a/zuul.d/pipelines.yaml b/zuul.d/pipelines.yaml
index 254b176..523127b 100644
--- a/zuul.d/pipelines.yaml
+++ b/zuul.d/pipelines.yaml
@@ -57,11 +57,11 @@
         - event: pull_request_review
           action: submitted
           state:
-            - approved
+            - 'approved'
         - event: pull_request_review
           action: dismissed
           state:
-            - request_changes
+            - 'request_changes'
         - event: check_run
           action: rerequested
           check: '.*/gate:.*'