only update pkgdown on push to main

Author: stopsack

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

@@ -160,7 +160,7 @@ jobs:
         shell: Rscript {0}
 
       - name: Deploy to GitHub pages 🚀
-        if: github.ref != 'refs/heads/dev' && matrix.config.os == 'ubuntu-latest'
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main' && matrix.config.os == 'ubuntu-latest'
         uses: JamesIves/github-pages-deploy-action@v4.4.1
         with:
           clean: false