Update README.md

Author: norberttech

README.md

@@ -20,7 +20,7 @@ This library goal is to resolve all above mentioned issues.
 ### Installations
 
 ```
-composer install amazon-php/sp-api-sdk^1.0@dev
+composer install amazon-php/sp-api-sdk^1.0
 ```
 
 This library is not in a stable stage yet, please use with caution.
@@ -224,4 +224,4 @@ $configuration->registerExtension(new class implements \AmazonPHP\SellingPartner
             . $response->getStatusCode() . " rate limit: " . implode(' ', $response->getHeader('x-amzn-RateLimit-Limit')) . "\n";
     }
 });
-```
+```