Update WordPress plugin link in README

Author: kirilkirkov

README.md

@@ -40,7 +40,7 @@ $config['base_url'] = defined('BASE_URL') ? BASE_URL : 'https://your-website.com
   - **Password:** admin
 
 ## Download as WordPress Plugin
-<a href="https://codecanyon.net/item/wp-invoices-pdf-electronic-invoicing-system/36891583">Available for integration with WordPress as a plugin.</a>
+<a href="https://wordpress.org/plugins/kirilkirkov-pdf-invoice-manager/">Available for integration with WordPress as a plugin.</a>
 
 ## Screenshots
 - **PDF Invoice:** ![alt text](https://raw.githubusercontent.com/kirilkirkov/ei/master/design/user/design_of_invoice.png?token=ADQ0kH5ObqDK3l2H-K4gXn74aIeVi0fVks5acX1HwA%3D%3D "Logo Title Text 1")
@@ -51,4 +51,4 @@ $config['base_url'] = defined('BASE_URL') ? BASE_URL : 'https://your-website.com
 ## Donate
 If this project helps you save time in development, consider buying me a cup of coffee to support its ongoing development. Thank you!
 
-[![Donate](https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif)](https://www.paypal.com/donate/?hosted_button_id=PF5ES4K748ZEY)
+[![Donate](https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif)](https://www.paypal.com/donate/?hosted_button_id=PF5ES4K748ZEY)