ci: run unit tests via GitHub actions

.github/workflows/test.yml

@@ -0,0 +1,20 @@
+name: Unit Tests
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '16'
+
+      # Install
+      - name: Install dependencies via yarn 📦
+        run: yarn install --prefer-offline --frozen-lockfile
+
+      # Run unit tests 🚀
+      - name: Run tests
+        run: yarn test