Include MFA Warning in Package Readme

Author: AdrianJSClark

src/Aydsko.iRacingData/Package README.md

@@ -1,9 +1,17 @@
-# Aydsko iRacing Data API
+# Aydsko iRacing Data API
 
 [iRacing](https://www.iracing.com) is the leading online racing simulation for PC. During events hosted via the iRacing service there is a large amount of data created related to race results and member participation in events.
 
 This library allows access via .NET to the iRacing "Data API". These APIs allow a properly authenticated user a supported method of accessing data from the service.
 
+## ⚠ Upcoming Multi-Factor Authentication Requirement
+
+iRacing has announced that they will be requiring multi-factor authentication (MFA) for all users by default. This will affect the ability to use the iRacing Data API by logging in with a username or password.
+
+In the immediate future, use of the Data API will be supported by enabling "Legacy Authentication" in your iRacing account settings. iRacing will advise next steps for the authentication of applications for the Data API later on.
+
+To continue to use this library you **must** enable "Legacy Authentication" in your iRacing account settings when that feature becomes available.
+
 ## Getting Started
 
 **1. Install the Aydsko iRacing Data API library.**