Update history for V4.2.1 release (#1164)

* Update history

* Update history

Author: tony-josi-aws

History.txt

@@ -1,5 +1,8 @@
 Documentation and download available at https://www.FreeRTOS.org/
 
+Changes between FreeRTOS-plus-TCP V4.2.1 and V4.2.0 released June 27, 2024
+    + Update version information in source files.
+
 Changes between FreeRTOS-plus-TCP V4.2.0 and V4.1.0 released June 24, 2024
     + It was possible for a carefully crafted DNS response with domain name
       length value greater than the actual domain name length, to cause a buffer