Don't need r-version

Author: andrjohns

.github/workflows/main.yml

@@ -91,6 +91,7 @@ jobs:
     - uses: r-lib/actions/setup-r@v2
       if: runner.os == 'Windows'
       with:
+        install-r: false
         rtools-version: '45'
 
     - name: Set path for Rtools45