ci(blocked-prs): use object filter to check pr label

https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/evaluate-expressions-in-workflows-and-actions#example-using-an-object-filter

Signed-off-by: Seth Flynn <getchoo@tuta.io>

.github/workflows/merge-blocking-pr.yml

@@ -12,7 +12,7 @@ jobs:
 
     # a pr that was a `blocking:<id>` label was merged.
     # find the open pr's it was blocked by and trigger a refresh of their state
-    if: github.event.pull_request.merged == true && contains( join( github.event.pull_request.labels.*.name, ',' ), 'blocking' )
+    if: github.event.pull_request.merged == true && contains(github.event.pull_request.labels.*.name, 'blocking')
 
     steps:
       - name: Generate token