Update actions/cache action to v4

Author: renovate[bot]

Diff for: .github/workflows/tests.yml

@@ -10,7 +10,7 @@ jobs:
       - name: Checkout Code
         uses: actions/checkout@v2
       - name: Cache node modules
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.npm
           key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}