Update tests.yaml

Author: skl

tests.yaml

@@ -599,7 +599,7 @@ tests:
       exp_annotations:
         summary: "Node is not ready."
         description: 'minikube has been unready for more than 15 minutes.'
-        runbook_url: 'https://github.com/kubernetes-monitoring/kubernetes-mixin/tree/master/runbook.md#alert-name-kubenodenotready"'
+        runbook_url: 'https://github.com/kubernetes-monitoring/kubernetes-mixin/tree/master/runbook.md#alert-name-kubenodenotready'
 
 - interval: 1m
   input_series: