Update actions/cache action to v4

Author: renovate[bot]

.github/workflows/continuous-integration.yml

@@ -33,7 +33,7 @@ jobs:
               run: echo "::set-output name=dir::$(composer config cache-files-dir)"
 
             - name: Cache dependencies
-              uses: actions/cache@v3
+              uses: actions/cache@v4
               with:
                   path: ${{ steps.composer-cache.outputs.dir }}
                   key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}