Update README.md

Author: glslang

README.md

@@ -1,6 +1,6 @@
 # setup-masm [![Build Status](https://github.com/glslang/setup-masm/actions/workflows/ci.yaml/badge.svg)](https://github.com/glslang/setup-masm/actions) [![GitHub release](https://img.shields.io/github/v/release/glslang/setup-masm?logo=github)](https://github.com/marketplace/actions/setup-masm)
 
-A GitHub Action to facilitate configuring MASM (Microsoft Macro Assembler) in the workflow PATH to use x86 or x64 assembly in Win32 applications.
+A GitHub Action to facilitate configuring MASM (Microsoft Macro Assembler) in the workflow PATH to use x64, x86 and ARM64 assembly in Win32 applications.
 
 ## Description