Update README.md

Author: AngusJohnson

README.md

@@ -83,7 +83,7 @@ https://github.com/AngusJohnson/Clipper2/blob/fa7add77364eb3877dd1b8caf9b3cbd548
 
 <details open>
   <summary><b>C++</b></summary>
-https://github.com/AngusJohnson/Clipper2/blob/2ad4894955e164be8d4c327e90ee8f3627252910/CPP/Examples/UsingZ/UsingZ.cpp#L173-L184
+https://github.com/AngusJohnson/Clipper2/blob/2970649befb89af85e2132e5242a7d6926cbfa11/CPP/Examples/UsingZ/UsingZ.cpp#L173-L184
 </details>
 
 ![coral3_t2](https://github.com/user-attachments/assets/fc1c8741-e033-4dc6-869a-c0d7da550cfa)