Add GH Action to upload releases to PyPi

.github/workflows/pypi-upload.yml

@@ -0,0 +1,46 @@
+# Copyright cocotb contributors
+# Licensed under the Revised BSD License, see LICENSE for details.
+# SPDX-License-Identifier: BSD-3-Clause
+
+name: Publish to PyPi
+
+on:
+  push:
+    branches:
+      - master
+      - 'stable/**'
+    tags:
+      - 'v*'
+
+jobs:
+  pypi-upload:
+    runs-on: ubuntu-latest
+    name: deploy
+    steps:
+    - uses: actions/checkout@master
+      with:
+        # To generate a valid version number setuptools_scm needs sufficient
+        # git history.
+        fetch-depth: 0
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: "3.9"
+    - name: Install pypa/build
+      run: >-
+        python -m
+        pip install
+        build
+        --user
+    - name: Build a source tarball
+      run: >-
+        python -m
+        build
+        --sdist
+        --outdir dist/
+        .
+    - name: Publish distribution to PyPI
+      if: startsWith(github.ref, 'refs/tags')
+      uses: pypa/gh-action-pypi-publish@master
+      with:
+        password: ${{ secrets.PYPI_API_TOKEN }}