Update README to include MacOS ARM64 support (#9)

Added MacOS ARM64 to the supported platforms list.

Author: lucarin91

README.md

@@ -6,6 +6,7 @@ This repository contains the release pipeline to build [qdl](https://github.com/
 - Linux ARMv6
 - Linux ARM64
 - MacOS 64bit
+- MacOS ARM64
 - Windows 32bit
 
 The compilation workflow uses the [arduino/crossbuild](https://github.com/arduino/crossbuild) docker image, wich container all the needed dependencies and toolchanin.