Add Github Actions (PR #2)

Author: julienw

.github/workflows/test.yml

@@ -0,0 +1,9 @@
+name: test
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - run: yarn
+      - run: yarn test