Add GitHub Actions config.

.github/workflows/python-package.yml

@@ -0,0 +1,34 @@
+name: Python package
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: [3.7, 3.8, 3.9]
+        django-version: [2.0, 2.1, 2.2, 2.3, 3.0, 3.1, 3.2]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install deps
+      run: |
+        python -m pip install pytest coverage coveralls "Django~=${{ matrix.django-version }}.0"
+    - name: Run tests
+      env:
+        GITHUB_TOKEN: ${{ secrets.github_token }}
+      run: |
+        echo "Python ${{ matrix.python-version }} & Django ${{ matrix.django-version }}"
+        coverage run --source=sitetree setup.py test
+        coveralls --service=github