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

Author: renovate[bot]

.github/workflows/build.yml

@@ -34,7 +34,7 @@ jobs:
           extensions: mbstring
 
       - name: "Cache dependencies"
-        uses: "actions/cache@v2"
+        uses: "actions/cache@v4"
         with:
           path: "~/.composer/cache"
           key: "php-${{ matrix.php-version }}-composer-${{ hashFiles('**/composer.json') }}"