fix: badge 150px with white background, constrain in README

Author: Rxflex

README.md

@@ -12,7 +12,7 @@ Shield is a self-hosted Telegram moderation and anti-spam bot. It watches group
 
 [![build](https://github.com/redstone-md/shield/actions/workflows/ci.yml/badge.svg)](https://github.com/redstone-md/shield/actions/workflows/ci.yml) [![Go Report Card](https://goreportcard.com/badge/github.com/redstone-md/shield)](https://goreportcard.com/report/github.com/redstone-md/shield)
 
-<img src="site/powered_by.png" alt="Powered by redstone.md"/>
+<img src="site/powered_by.png" alt="Powered by redstone.md" width="150"/>
 
 </div>