Updated Board NUCLEO F401RE (markdown)

Board-NUCLEO-F401RE.md

@@ -19,6 +19,7 @@ NUCLEO-F401RE
 * Initial support
   * [nuraci](https://github.com/nuraci/micropython)
   * [cnoviello](https://github.com/cnoviello/micropython)
+(Please note: These forks are out of date. The last commits were Dec 3, 2014, and Aug 11, 2015 respectively)
 * test in progress
 
 ### How build for ###