Update README.md (#82)

Author: haris-musa

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <img src="assets/logo.png" alt="Excel MCP Server Logo" width="300"/>
+  <img src="https://raw.githubusercontent.com/haris-musa/excel-mcp-server/main/assets/logo.png" alt="Excel MCP Server Logo" width="300"/>
 </p>
 
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