Update .github/workflows/stale.yaml

Co-authored-by: Ruben Hönle <Ruben.Hoenle@stackit.cloud>

Author: marceljk

.github/workflows/stale.yaml

@@ -11,7 +11,7 @@ on:
 env:
   DAYS_BEFORE_PR_STALE: 7
   DAYS_BEFORE_PR_CLOSE: 7
-  EXEMPT_PR_LABELS: "ignore stale"
+  EXEMPT_PR_LABELS: "ignore-stale"
 
 permissions:
   issues: write