Update README.md

Author: webflo

README.md

@@ -15,7 +15,7 @@ This package ensures that your application doesn't have installed dependencies w
 ### Drupal 7 ([composer.json](https://github.com/drupal-composer/drupal-security-advisories/blob/7.x/composer.json))
 
 ```sh
-~$ composer require drupal-composer/drupal-security-advisories:9.x-dev
+~$ composer require drupal-composer/drupal-security-advisories:7.x-dev
 ```
 
 # Usage