Suggest dependencies instead of requiring them

.github/workflows/phpstan.yml

@@ -5,10 +5,14 @@ jobs:
     name: Custom rules check
     runs-on: ubuntu-latest
     steps:
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 7.4
+
       - name: Checkout
         uses: actions/checkout@v2.0.0
 
-
       # Docker images prestashop/prestashop may be used, even if the shop remains uninstalled
       - name: Run constant test
         run: |

composer.json

@@ -5,11 +5,16 @@
   "require": {
     "php": ">=7.2.5",
     "symfony/console": "~3.2 || ~4.0 || ~5.0 || ~6.0 || ~7.0",
-    "friendsofphp/php-cs-fixer": "^3.2",
-    "squizlabs/php_codesniffer": "^3.4",
-    "symfony/filesystem": "~3.2 || ~4.0 || ~5.0 || ~6.0 || ~7.0",
+    "symfony/filesystem": "~3.2 || ~4.0 || ~5.0 || ~6.0 || ~7.0"
+  },
+  "require-dev": {
+    "friendsofphp/php-cs-fixer": "^3.2"
+  },
+  "suggest": {
     "prestashop/header-stamp": "^2.0",
-    "prestashop/autoindex": "^2.0"
+    "prestashop/autoindex": "^2.0",
+    "squizlabs/php_codesniffer": "^3.4",
+    "phpstan/phpstan": "^0.12"
   },
   "bin": [
     "bin/prestashop-coding-standards"
@@ -24,5 +29,5 @@
       "php": "7.2.5"
     }
   },
-  "author": "PrestaShop"
+  "authors": [{"name": "PrestaShop"}]
 }