chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -39,7 +39,7 @@ jobs:
         run: curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/bin --filename=composer --version=2.9.2
 
       - name: "Checkout"
-        uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           show-progress: false