chore(deps): update actions/checkout action to v4

Author: smartway-bot[bot]

.github/workflows/unit-tests.yml

@@ -15,7 +15,7 @@ jobs:
         uses: mickem/clean-after-action@v2
 
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - uses: actions/setup-node@v3
         with: