Update README.md

Set the first Open in MATLAB Online badge to open to the README.

Author: eszmw

README.md

@@ -3,7 +3,7 @@
 # <span style="color:rgb(213,80,0)">Programming: Structuring Code</span>
 <a name="H_053613DF"></a>
 
-[![View on File Exchange](https://www.mathworks.com/matlabcentral/images/matlab-file-exchange.svg)](https://www.mathworks.com/matlabcentral/fileexchange/115905-programming-structuring-code) or [![Open in MATLAB Online](https://www.mathworks.com/images/responsive/global/open-in-matlab-online.svg)](https://matlab.mathworks.com/open/github/v1?repo=MathWorks-Teaching-Resources/Programming-Structuring-Code&project=StructuringCode.prj)
+[![View on File Exchange](https://www.mathworks.com/matlabcentral/images/matlab-file-exchange.svg)](https://www.mathworks.com/matlabcentral/fileexchange/115905-programming-structuring-code) or [![Open in MATLAB Online](https://www.mathworks.com/images/responsive/global/open-in-matlab-online.svg)](https://matlab.mathworks.com/open/github/v1?repo=MathWorks-Teaching-Resources/Programming-Structuring-Code&project=StructuringCode.prj&file=README.mlx)
 
 ![MATLAB Versions Tested](https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2FMathWorks-Teaching-Resources%2FProgramming-Structuring-Code%2Frelease%2FImages%2FTestedWith.json)