devops: Run CI jobs also on Python 3.9 (#226)

Author: mxschmitt

.github/workflows/ci.yml

@@ -33,6 +33,16 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
         python-version: [3.7, 3.8]
         browser: [chromium, firefox, webkit]
+        include:
+        - os: ubuntu-latest
+          python-version: 3.9
+          browser: chromium
+        - os: windows-latest
+          python-version: 3.9
+          browser: chromium
+        - os: macos-latest
+          python-version: 3.9
+          browser: chromium
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2
@@ -43,7 +53,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip wheel
         pip install -r local-requirements.txt
         pip install -e .
     - name: Build package

local-requirements.txt

@@ -5,10 +5,11 @@ pytest-sugar==0.9.4
 pytest-xdist==2.1.0
 pytest-timeout==1.4.2
 pixelmatch==0.2.1
-Pillow==7.2.0
+Pillow==8.0.0
 mypy==0.782
 setuptools==50.3.0
-twisted==20.3.0
+# TODO: use PyPi version after >20.3.0 is released
+git+https://github.com/twisted/twisted.git@4ff22287cab3b54f51cee41ea2619e72d1bff2e4
 wheel==0.35.1
 black==20.8b1
 pre-commit==2.7.1

setup.py

@@ -35,6 +35,7 @@
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "License :: OSI Approved :: Apache Software License",
         "Operating System :: OS Independent",
     ],