Add a GiHub actions workflow for releases

.github/workflows/release_triggerd_build_and_upload_to_pypi.yml

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+
+name: Build PySOEM sdist and wheels and upload them to PyPI
+
+# This is triggerd upon creating a release on GitHub.
+on:
+  release:
+    types: [published]
+
+jobs:
+  build_wheels:
+    name: Build wheels on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, windows-2019]
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: recursive
+
+      - name: Build wheels
+        uses: pypa/[email protected]
+
+      - uses: actions/upload-artifact@v3
+        with:
+          path: ./wheelhouse/*.whl
+
+  build_sdist:
+    name: Build source distribution
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Build sdist
+        run: pipx run build --sdist
+
+      - uses: actions/upload-artifact@v3
+        with:
+          path: ./dist/*.tar.gz
+
+  upload_pypi:
+    needs: [build_wheels, build_sdist]
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/download-artifact@v3
+        with:
+          name: artifact
+          path: dist
+
+      - uses: pypa/[email protected]
+        with:
+          user: __token__
+          password: ${{ secrets.PYPI_PYSOEM_ACCESS_TOKEN }}