Trying to install graphviz depdency for vignettes

Author: davidrsch

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

@@ -62,7 +62,11 @@ jobs:
         if: runner.os == 'Linux'
         run: |
           sudo apt-get update
-          sudo apt-get install -y qpdf ghostscript
+          sudo apt-get install -y qpdf ghostscript graphviz
+        if: runner.os == 'macOS'
+        run: brew install graphviz
+        if: runner.os == 'Windows'
+        run: choco install graphviz -y
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with: