Separate tests and release workflows

.github/workflows/main.yml

@@ -59,10 +59,3 @@ jobs:
         coveralls --service=github
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-    - name: Publish a Python distribution to PyPI
-      uses: pypa/gh-action-pypi-publish@master
-      if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
-      with:
-        user: ${{ secrets.PYPI_USER }}
-        password: ${{ secrets.PYPI_PASSWORD }}

.github/workflows/release.yml

@@ -0,0 +1,25 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: install pypa/build
+      run: python -m pip install build --user
+
+    - name: build a binary whell and a source tarball
+      run: python -m build --sdist --wheel --outdir dist/ .
+
+    - name: Publish a Python distribution to PyPI
+      uses: pypa/gh-action-pypi-publish@master
+      with:
+        user: ${{ secrets.PYPI_USER }}
+        password: ${{ secrets.PYPI_PASSWORD }}