stale-blocked: Apply the stale label so that closed PRs are not locked

.github/workflows/stale-blocked.yml

@@ -33,11 +33,14 @@ jobs:
             checks for {days} days. It is not ready for inclusion. It is being
             automatically closed.
           EXEMPT_LABEL: "leave-open"
+          CLOSE_LABEL: "Stale"
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
             const labelBlocked = process.env.LABEL_BLOCKED || "blocked";
             const labelChecks  = process.env.LABEL_CHECKS  || "pr-check-blocked";
+            const labelStale   = process.env.LABEL_STALE   || "Stale";
+
             const daysThreshold = parseInt(process.env.DAYS_THRESHOLD || "14", 10);
             const exemptLabel = process.env.EXEMPT_LABEL || "leave-open";
             const dryRun = process.env.DRY_RUN === "true";
@@ -155,6 +158,12 @@ jobs:
                       pull_number: pr.number,
                       state: "closed"
                     });
+                    await github.rest.issues.addLabels({
+                      owner: context.repo.owner,
+                      repo: context.repo.repo,
+                      issue_number: pr.number,
+                      labels: [labelStale]
+                    });
                   }
                 }
               } catch (err) {