trying to fix macos check error

Author: davidrsch

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

@@ -66,7 +66,7 @@ jobs:
 
       - name: Install system dependencies for vignettes (macOS)
         if: runner.os == 'macOS'
-        run: brew install graphviz
+        run:  brew install qpdf ghostscript graphviz
 
       - name: Install system dependencies for vignettes (Windows)
         if: runner.os == 'Windows'