Update README.md

Additional update for the change to MIT license.

README.md

@@ -185,7 +185,7 @@ Finally, I am occasionally able to offer paid support for situations where you n
 
 I welcome contributions to NAudio and have accepted many patches, but if you want your code to be included, please familiarise yourself with the following guidelines:
 
-* Your submission must be your own work, and able to be released under the MS-PL license.
+* Your submission must be your own work, and able to be released under the MIT license.
 * You will need to make sure your code conforms to the layout and naming conventions used elsewhere in NAudio.
 * Remember that there are many existing users of NAudio. A patch that changes the public interface is not likely to be accepted.
 * Try to write "clean code" - avoid long functions and long classes. Try to add a new feature by creating a new class rather than putting loads of extra code inside an existing one.