Adds a CI workflow for checking lint and formatting.

.github/workflows/build-test-release.yaml

@@ -0,0 +1,29 @@
+name: Build / Test / Release
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  lint-format:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [3.6, 3.7, 3.8]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install requirements
+        run: |
+          python -m pip install --upgrade pip
+          pip install black==19.10b0 flake8==3.7.9 flake8-bugbear==19.8.0
+      - name: Check lint
+        run: flake8 .
+      - name: Check format
+        run: black --check .