Update URL in history.txt (#259)

* Update URL in history.txt

* Configure CI header checker to ignore .txt files

Co-authored-by: alfred gedeon <28123637+alfred2g@users.noreply.github.com>

Author: jefftenney

History.txt

@@ -79,7 +79,7 @@ Changes between FreeRTOS V10.3.1 and FreeRTOS V10.4.0 released September 10 2020
 	  the same way the Windows port layer enables FreeRTOS to run on Windows
 	  hosts.
 	+ Many other minor optimisations and enhancements. For full details  
-	  see https://github.com/FreeRTOS/FreeRTOS-Kernel/commits/master
+	  see https://github.com/FreeRTOS/FreeRTOS-Kernel/commits/main
 
 
 Changes between FreeRTOS V10.3.0 and FreeRTOS V10.3.1 released February 18 2020