GHA: use debug-shell action

Author: gaborcsardi

.github/workflows/R-CMD-check.yaml

@@ -59,6 +59,8 @@ jobs:
           extra-packages: any::rcmdcheck
           needs: check
 
+      - uses: r-hub/actions/debug-shell@v1
+
       - uses: r-lib/actions/check-r-package@v2
         with:
           upload-snapshots: true