Move all testing to github actions

The Travis CI folks are updating stuff and broke my tests, so I'm moving
over to github actions instead since that is (hopefully) less likely to
change moving forward.

Will need to move PyPi deployment to github actions as well.

.github/workflows/tests.yml

@@ -0,0 +1,18 @@
+name: tests
+
+on:
+  push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: '3.x'
+    - name: Install dependencies
+      run: pip install -r requirements.txt
+    - name: Run tests
+      run: ./run test