Update README.md

Co-authored-by: Vassil Vassilev <[email protected]>

Author: salva24

README.md

@@ -85,7 +85,7 @@ biodynamo run
 **Option 2:**  
 Directly from the build directory:
 ```bash
-./build/cart_tumor
+./build/CARTopiaX
 ```
 
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