Add disclaimer to README

Author: MrLightful

README.md

@@ -5,3 +5,9 @@ Unofficial SDK for Python to integrate with Braspag payment gateway.
 ```bash
 pip install --upgrade braspag-sdk
 ```
+
+## Disclaimer
+This SDK is created for personal use and is not officially supported by Braspag/Cielo.
+The functionality is limited to what I need for my own projects.
+You are more than welcome to contribute the functionality that you need as soon as it follows the same code style.
+Fortunately, this is a very simple SDK, so it should be easy to understand and extend.