Update README.md

Author: Athlon1600

README.md

@@ -11,12 +11,9 @@ from popular search engines like Google and Bing.
 The recommended way to install this is via Composer:
 
 ```bash
-composer require athlon1600/serpscraper "^3.0"
+composer require athlon1600/serpscraper "^4.0"
 ```
 
-old version:  
-https://github.com/Athlon1600/SerpScraper/tree/2.x  
-
 ## Extracting Search Results From Google
 
 ```php