Publish pre-compiled wheels for Win32 (#199)

+name: build-wheels-win32
+
+on:
+  push:
+    branches:
+      - wheel
+    tags:
+      - '*'
+
+env:
+  SHERPA_ONNX_IS_IN_GITHUB_ACTIONS: 1
+
+concurrency:
+  group: build-wheels-win32-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build_wheels_win32:
+    name: Build wheels on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      # see https://cibuildwheel.readthedocs.io/en/stable/changelog/
+      # for a list of versions
+      - name: Build wheels
+        uses: pypa/cibuildwheel@v2.11.4
+        env:
+          CIBW_BEFORE_BUILD: "pip install -U cmake numpy"
+          CIBW_ENVIRONMENT: SHERPA_ONNX_CMAKE_ARGS="-A Win32"
+          CIBW_SKIP: "*-win_amd64"
+          CIBW_BUILD_VERBOSITY: 3
+
+      - name: Display wheels
+        shell: bash
+        run: |
+          ls -lh ./wheelhouse/
+
+          ls -lh ./wheelhouse/*.whl
+
+      - uses: actions/upload-artifact@v2
+        with:
+          path: ./wheelhouse/*.whl
+
+      - name: Publish wheels to PyPI
+        env:
+          TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
+          TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
+        run: |
+          python3 -m pip install --upgrade pip
+          python3 -m pip install wheel twine setuptools
+
+          twine upload ./wheelhouse/*.whl