doc: update readme to include license badge

Author: manusa

README.md

@@ -1,6 +1,9 @@
 # Kubernetes MCP Server
 
 <p align="center">
+  <a href="https://github.com/manusa/kubernetes-mcp-server/blob/main/LICENSE">
+    <img alt="GitHub License" src="https://img.shields.io/github/license/manusa/kubernetes-mcp-server">
+  </a>
   <a href="https://github.com/manusa/kubernetes-mcp-server/actions/workflows/build.yaml">
     <img src="https://github.com/manusa/kubernetes-mcp-server/actions/workflows/build.yaml/badge.svg" alt="Build status badge" />
   </a>
@@ -11,7 +14,7 @@
   <a href="#features">Features</a>
 </p>
 
-## Features <a id="features" />
+## ✨ Features <a id="features" />
 
 ## Notes