Merge pull request #4552 from YosysHQ/krys/rtd_on_main

docs: Only trigger RTDs on main

.github/workflows/test-verific.yml

@@ -112,6 +112,7 @@ jobs:
             docs/source/code_examples
 
       - name: Trigger RTDs build
+        if: ${{ github.ref == 'refs/heads/main' }}
         uses: dfm/rtds-action@v1.1.0
         with:
           webhook_url: ${{ secrets.RTDS_WEBHOOK_URL }}