Updated History.txt for task notification array change (#65)

Updated History.txt to note the single task notification per task has been replaced with an array of task notifications per task.
diff --git a/History.txt b/History.txt
index 243e3c3..b8cdd96 100644
--- a/History.txt
+++ b/History.txt
@@ -4,8 +4,10 @@
 

 	See http://www.FreeRTOS.org/FreeRTOS-V10.3.x.html

 

-	./FreeRTOS-Labs directory was removed from this file. The libraries it 

+	+ ./FreeRTOS-Labs directory was removed from this file. The libraries it

 	contained are now available as a separate download.

+	+ Replaced the single task notification per task with an array of

+	notificatinos per task.

 

 Changes between FreeRTOS V10.2.1 and FreeRTOS V10.3.0 released February 7 2020