v1.2.1 to fix bug of wrong reqStates

### Release v1.2.1

1. Fix bug of wrong `reqStates`. Check [Release 1.9 breakes previously running code #39](khoih-prog/AsyncHTTPRequest_Generic#39) and [Callback behaviour is buggy (ESP8266) #43](khoih-prog/AsyncHTTPRequest_Generic#43)
2. Optional larger `DEFAULT_RX_TIMEOUT` from default 3s, for slower networks

Author: khoih-prog

changelog.md

@@ -11,6 +11,7 @@
 ## Table of Contents
 
 * [Changelog](#changelog)
+  * [Release v1.2.1](#Release-v121)
   * [Release v1.2.0](#Release-v120)
   * [Release v1.1.1](#Release-v111)
   * [Release v1.1.0](#Release-v110)