try adding a label the same way as the other step

Forks don't generally get access to the access token but lets see if this works

.github/workflows/pr-manage-stale.yml

@@ -24,12 +24,26 @@ jobs:
   new_pull_request:
     if: ${{ github.event_name == 'pull_request' }}
     runs-on: ubuntu-latest
-    steps:
-      - name: add labels
-        uses: actions-ecosystem/action-add-labels@v1
-        with:
-          labels: |
-            Age: 🥚 - New
+    steps:            
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: add label
+        shell: pwsh
+        run: |
+          # ensure labels exist - create them if they don't
+          # https://docs.github.com/en/rest/reference/issues#create-a-label      
+          $label = "Age: 🥚 - New"
+          $description = "About 2 hours old"
+          Write-Output "Ensuring label exists: $label ($description))"
+          gh api repos/${{ github.repository }}/labels -f name="$label" -f color=000000 -f description="$description"
+
+          $thisPr = gh pr view ${{ github.number }} --json number,isCrossRepository
+          Write-Output "Adding label: $label"
+          gh pr edit $thisPr.number --add-label "$label"
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
 
   scheduled_run:
     if: ${{ github.event_name != 'pull_request' }}