Typo in how to perform check for specific labels (actions#357)

Not tests but feels like a typo.

Or if we keep the title it `exempt` feels more approriate:

          exempt-issue-labels: 'roadmap'
          exempt-pr-labels: 'roadmap'

README.md

@@ -229,7 +229,7 @@ jobs:
           exempt-all-pr-milestones: true
 ```
 
-Avoid stale for specific labels:
+Check stale for specific labels:
 
 ```yaml
 name: 'Close stale issues and PRs'