Move to GitHub actions.

.github/workflows/python-package.yml

@@ -0,0 +1,35 @@
+name: build
+on:
+  push:
+    branches: 
+      - master
+  pull_request:
+    branches:
+      - master
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version:
+          - 3.6
+          - 3.7
+          - 3.8
+          - 3.9
+    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 dependencies
+        run: |
+          pip install --upgrade pip
+          pip install flake8 pytest .
+      - name: Lint with flake8
+        run: |
+          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+          flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+      - name: Test with pytest
+        run: |
+          pytest