Merge pull request #3 from pikalab-unibo/renovate/actions-checkout-4.x

Update actions/checkout action to v4

.github/workflows/compile.yml

@@ -12,7 +12,7 @@ jobs:
         run: sudo sed -i 's/rights=".*"/rights="all"/' /etc/ImageMagick-6/policy.xml
       # Checkout the repository
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Fetch tags