Add arm64 Windows build to CI

Author: ad-si

.github/workflows/build.yml

@@ -23,6 +23,8 @@ jobs:
             target: aarch64-unknown-linux-gnu
           - os: windows-latest
             target: x86_64-pc-windows-msvc
+          - os: windows-11-arm
+            target: aarch64-pc-windows-msvc
 
     runs-on: ${{ matrix.os }}
     name: Build (${{ matrix.target }})