Update dev-hato/actions-add-to-projects action to v0.0.21 (#81)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/add-to-task-list.yml

@@ -13,7 +13,7 @@ jobs:
   add-to-task-list:
     runs-on: ubuntu-latest
     steps:
-      - uses: dev-hato/[email protected].20
+      - uses: dev-hato/[email protected].21
         with:
           github_app_id: ${{ secrets.PROJECT_AUTOMATION_APP_ID }}
           github_app_private_key: ${{ secrets.PROJECT_AUTOMATION_PRIVATE_KEY }}