Update test workflow

Author: jviide

.github/workflows/tests.yml

@@ -9,12 +9,8 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v2
         with:
-          node-version: "14.x"
-      - uses: actions/cache@v2
-        with:
-          path: ~/.npm
-          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-node-
+          node-version: "16"
+          cache: npm
+          registry-url: https://registry.npmjs.org/
       - run: npm ci
       - run: npm test