chore: add test workflows

.github/workflows/test.yml

@@ -0,0 +1,14 @@
+name: github pages
+
+on:
+  push:
+    branches:
+      - next # default branch
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - run: yarn install
+      - run: yarn test