v1.4.4 to change license to GPLv3

### Releases v1.4.4

1. Change license from `MIT` to `GPLv3`. Check [Licensing of SSLClient #16](khoih-prog/EthernetWebServer_SSL#16)

Author: khoih-prog

CONTRIBUTING.md

@@ -29,7 +29,7 @@ Please ensure to specify the following:
 Arduino IDE version: 1.8.19
 STM32F7 Nucleo-144 NUCLEO_F767ZI, STM32 core v2.2.0
 OS: Ubuntu 20.04 LTS
-Linux xy-Inspiron-3593 5.4.0-100-generic #113-Ubuntu SMP Thu Feb 3 18:43:29 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
+Linux xy-Inspiron-3593 5.13.0-35-generic #40~20.04.1-Ubuntu SMP Mon Mar 7 09:18:32 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
 
 Context:
 I encountered a crash while trying to use the Timer Interrupt.
@@ -49,3 +49,4 @@ There are usually some outstanding feature requests in the [existing issues list
 ### Sending Pull Requests
 
 Pull Requests with changes and fixes are also welcome!
+