chore: node16 for github action

.github/workflows/tests.yml

@@ -5,6 +5,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '16'
       - name: Install modules
         run: yarn
       - name: Run unit tests