only push to pypi if the PR is merged to main

.github/workflows/build_wheels.yml

@@ -1,4 +1,4 @@
-name: build package wheel
+name: build macos and windows wheels
 
 on:
   push:
@@ -35,14 +35,30 @@ jobs:
       - name: Build Wheel with Flit
         run: flit build
 
+      - name: Test Install Wheel
+        run: pip install dist/*.whl
+
       - name: Upload to GitHub Artifacts
         uses: actions/upload-artifact@v2
         with:
           name: python-package
           path: dist/*.whl
 
+  publish-to-pypi:
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.x" # Use the latest version of Python 3
+
+      - name: Install Flit
+        run: python -m pip install flit
+
       - name: Publish to PyPI
-        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
         run: flit publish --repository pypi
         env:
           FLIT_USERNAME: ${{ secrets.PYPI_USERNAME }}