Move wpsyntex/polylang-stubs to dev dependencies. (#22)

* Move wpsyntex/polylang-stubs to dev dependencies.

* Update README.

Author: Hug0-Drelon

README.md

@@ -33,7 +33,7 @@ Include the extension and stubs in the PHPStan configuration file.
 includes:
   - vendor/wpsyntex/polylang-phpstan/extension.neon
 parameters:
-  stubFiles:
+  scanFiles:
     - vendor/wpsyntex/polylang-stubs/polylang-stubs.php
 ```
 

composer.json

@@ -6,11 +6,11 @@
 	"type": "library",
 	"require": {
 		"php": "^8.0",
-		"szepeviktor/phpstan-wordpress": "^2.0",
-		"wpsyntex/polylang-stubs": "dev-master"
+		"szepeviktor/phpstan-wordpress": "^2.0"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "^9"
+		"phpunit/phpunit": "^9",
+		"wpsyntex/polylang-stubs": "dev-master"
 	},
 	"autoload": {
 		"psr-4": {