Add auto pypi publish script

.github/workflows/publish_pypi.yaml

@@ -0,0 +1,32 @@
+name: Build and Publish to PyPI using Flit
+
+on:
+  push:
+    paths:
+      - 'src/exengine/_version.py'
+
+jobs:
+  build-and-publish:
+    runs-on: ubuntu-latest
+    permissions:
+      id-token: write  # This is required for requesting the JWT
+      contents: read  # This is required for actions/checkout
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: '3.x'
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install flit
+    - name: Install package dependencies
+      run: |
+        pip install -e .
+    - name: Set PYTHONPATH
+      run: echo "PYTHONPATH=$PYTHONPATH:${{ github.workspace }}/src" >> $GITHUB_ENV
+    - name: Build package
+      run: flit build
+    - name: Publish package distributions to PyPI
+      uses: pypa/gh-action-pypi-publish@release/v1