Add workflow for pushing to PyPI

.github/workflows/release.yml

@@ -0,0 +1,71 @@
+name: Release
+
+on: [push]
+
+# Releases work as follows (driven by ./scripts/release.py):
+#
+# 1. A non-tagged version with a relase `__version__` (anything not ending in
+#    `+dev` or `-dev`) is pushed to `master`. Since we always add the `+dev`
+#    suffix after a release, there will only ever be one such commit per
+#    release. This commit should trigger a release to Test-PyPI, in this
+#    workflow.
+#
+# 2. Once the workflows for the release commit pass, the commit is tagged as
+#    `v<__version__>` and the tag is pushed to Github. This triggers the
+#    automatic creation of an official "Release" on Github, and this workflow to release to the regular PyPI
+
+jobs:
+
+  push_release_to_pypi:
+    name: Push Package Release to PyPI
+    runs-on: ubuntu-18.04
+    steps:
+
+      - uses: actions/checkout@v2
+
+      - uses: actions/setup-python@v2
+        name: Install Python 3.8
+        with:
+          python-version: 3.8
+
+      - name: Install Prerequisites
+        run: pip install wheel twine
+
+      - name: Get the version
+        id: get_version
+        run: echo ::set-output name=VERSION::$(python -c 'print([line.split("=")[-1].strip()[1:-1] for line in open("./src/qalgebra/__init__.py", encoding="utf8").readlines() if line.startswith("__version__")][0], end="")')
+
+      - name: Get tag name
+        if: startsWith(github.ref, 'refs/tags/v')
+        shell: bash
+        run: |
+          echo ${{ github.ref }}
+          echo "TAG_NAME=$(echo ${GITHUB_REF##*/} | tr / -)" >> $GITHUB_ENV
+          cat $GITHUB_ENV
+
+      - name: Check that tag is release
+        if: startsWith(github.ref, 'refs/tags/v')
+        run: test "v${{ steps.get_version.outputs.VERSION }}" == "${{ env.TAG_NAME }}"
+
+      - name: Build Source and Wheel Package
+        run: |
+          python setup.py sdist
+          python setup.py bdist_wheel
+
+      - name: Check distribution files
+        run: twine check dist/*
+
+      - name: Publish package to Test - PyPI
+        if: github.event_name == 'push' && startsWith(github.ref, 'refs/heads/master') && ! endsWith(steps.get_version.outputs.VERSION, '-dev') && ! endsWith(steps.get_version.outputs.VERSION, '+dev')
+        uses: pypa/gh-action-pypi-publish@master
+        with:
+          user: __token__
+          password: ${{ secrets.TEST_PYPI_API_TOKEN }}
+          repository_url: https://test.pypi.org/legacy/
+
+      - name: Publish package to PyPI
+        if: startsWith(github.ref, 'refs/tags/v')
+        uses: pypa/gh-action-pypi-publish@master
+        with:
+          user: __token__
+          password: ${{ secrets.PYPI_API_TOKEN }}