Switch CI to Github actions

.github/workflows/test.yml

@@ -0,0 +1,24 @@
+name: Test
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [ 3.5, 3.6, 3.7, 3.8, 3.9, 2.7 ]
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          pip install pytest
+
+      - name: Run tests
+        run: pytest -v

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
-requires = ["flit"]
-build-backend = "flit.buildapi"
+requires = ["flit_core >=2,<4"]
+build-backend = "flit_core.buildapi"
 
 [tool.flit.metadata]
 module = "ptyprocess"