Add system deps for Rfast

Author: sterrettJD

.github/workflows/document.yaml

@@ -22,7 +22,11 @@ jobs:
       - uses: r-lib/actions/setup-r@v2
         with:
           use-public-rspm: true
-
+          
+      - name: Install system dependencies
+      # required for Rfast
+        run: sudo apt-get install -y libgomp1
+        
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
           extra-packages: any::roxygen2