Add error-on: note to R-CMD-check workflow to treat NOTEs as failures

Co-authored-by: osorensen <21175639+osorensen@users.noreply.github.com>

Author: Copilot

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

@@ -48,3 +48,4 @@ jobs:
         with:
           upload-snapshots: true
           build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'
+          error-on: 'note'