Add deploy workflow (#80)

* automated deployment action
* fix #79
* add deploy workflow for automatic uploads to testpypi (release tag) and pypi (GitHub release)
  (based on @IAlibay 's work for alchemlyb) with minor modifications
  - use alchemtest repo
  - use Python 3.9
* created tokens for PyPi and Test PyPi and added them to the repo environment
  "deploy" as TEST_PYPI_API_TOKEN and PYPI_API_TOKEN

Co-authored-by: Irfan Alibay <[email protected]>

.github/workflows/deploy.yaml

@@ -0,0 +1,64 @@
+name: Build and upload to PyPI
+
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - "*"
+  release:
+    types:
+      - published
+
+
+concurrency:
+  group: "${{ github.ref }}-${{ github.head_ref }}-${{ github.workflow }}"
+  cancel-in-progress: true
+
+
+defaults:
+  run:
+    shell: bash -l {0}
+
+
+jobs:
+  build_wheels:
+    environment: deploy
+    if: "github.repository == 'alchemistry/alchemtest'"
+    name: Build pure Python wheel and tarball
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: setup_miniconda
+        uses: conda-incubator/setup-miniconda@v2
+        with:
+          python-version: 3.9
+          auto-update-conda: true
+          add-pip-as-python-dependency: true
+          architecture: x64
+
+      - name: install_deps
+        run: |
+          python -m pip install build
+
+      - name: build
+        run: |
+          python -m build --sdist --wheel --outdir dist/
+ 
+      - name: publish_testpypi
+        # Upload to testpypi on every tag
+        if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
+        uses: pypa/gh-action-pypi-publish@master
+        with:
+          password: ${{ secrets.TEST_PYPI_API_TOKEN }}
+          repository_url: https://test.pypi.org/legacy/
+
+      - name: publish_pypi
+        if: github.event_name == 'release' && github.event.action == 'published'
+        uses: pypa/gh-action-pypi-publish@master
+        with:
+          password: ${{ secrets.PYPI_API_TOKEN }}