Add pyproject.toml and explicit build requirements (#109)

Add pyproject.toml with build-system information.
This information explicitly states to install jupyter_core (as well as
setuptools).

Update publish workflow.

Completely avoid running setup.py directly. This is deprecated.

.github/workflows/ci-build.yml

@@ -29,10 +29,6 @@ jobs:
         python -m pip install --upgrade pip
         pip install -U setuptools wheel
         pip install -U build
-        pip install -r requirements_base.txt
 
     - name: Build package with build
-      run: python -m build --sdist --wheel --outdir dist/
-
-    - name: Build package with setup.py
-      run: python setup.py sdist bdist_wheel
+      run: python -m build

.github/workflows/publish-on-pypi.yml

@@ -12,17 +12,17 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     - name: Set up Python 3.8
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
-        python-version: 3.8
+        python-version: "3.8"
 
     - name: Install Python dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -U setuptools
+        pip install -U setuptools wheel build
         pip install -U invoke
 
     - name: Update version
@@ -49,10 +49,10 @@ jobs:
         branch: develop
 
     - name: Build source distribution
-      run: python ./setup.py sdist
+      run: python -m build
 
     - name: Publish package to PyPI
-      uses: pypa/gh-action-pypi-publish@master
+      uses: pypa/gh-action-pypi-publish@release/v1
       with:
         user: __token__
         password: ${{ secrets.PYPI_PASSWORD }}

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools>=42.0.0", "jupyter_core>=5.3.1,<6"]
+build-backend = "setuptools.build_meta"