Fix: Cache key

Author: localheinz

.github/workflows/continuous-integration.yml

@@ -29,7 +29,7 @@ jobs:
         uses: "actions/cache@v1.0.3"
         with:
           path: "~/.composer/cache"
-          key: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-${{ hashFiles('**/composer.lock') }}"
+          key: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-${{ hashFiles('**/composer.json') }}"
           restore-keys: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-"
 
       - name: "Install dependencies with composer"