Update README.md

README.md

 
 - Before you submit any pull request, we ask that you _PLEASE_ test your code before submission, even if the change seems innocuous. When creating the pull request, please include the hardware you used for testing and a short synopsis of your testing procedure. Untested pull requests are less likely to be merged, as even slight changes create the risk of breaking the main branch.
 
-- If you have a fix don't open an issue telling about it, but test the code and submit a pull request.
+- If you have a fix don't open an issue telling about it, but test the code and submit a pull request. Use the __development__ branch when you submit, current its not the default one so please check that you submit to the __development__ branch
 
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 Marlin 3D Printer Firmware