👷 Add GitHub Actions, move from Travis (#1735)

.github/workflows/test.yml

@@ -0,0 +1,29 @@
+name: Test
+
+on:
+  push:
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [3.6, 3.7, 3.8]
+      fail-fast: false
+    
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python
+        uses: actions/setup-python@v1
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install Flit
+        run: pip install flit
+      - name: Install Dependencies
+        run: flit install --symlink
+      - name: Test
+        run: bash scripts/test.sh
+      - name: Upload coverage
+        uses: codecov/codecov-action@v1