Add jest workflow

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

.github/workflows/test.yaml

@@ -0,0 +1,18 @@
+name: Run jest tests
+on:
+  pull_request: {}
+jobs:
+  jest:
+    name: Run jest tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Yarn cache
+        uses: actions/setup-node@v3
+        with:
+          cache: "yarn"
+      - name: Install dependencies
+        run: "yarn install"
+      - name: Jest
+        run: "yarn run test"