Improve arch and system autodetection #52

[slavaGanzin]

Before:

stew i rancher-sandbox/rancher-desktop
rancher-sandbox/rancher-desktop
! Could not automatically detect the release asset matching your OS/Arch. Please select it manually:  [Use arrows to move, type to filter]
> rancher-desktop-linux-v1.16.0.zip
  rancher-desktop-linux-v1.16.0.zip.sha512sum
  Rancher.Desktop-1.16.0-mac.aarch64.zip
  Rancher.Desktop-1.16.0-mac.aarch64.zip.sha512sum
  Rancher.Desktop-1.16.0-mac.x86_64.zip
  Rancher.Desktop-1.16.0-mac.x86_64.zip.sha512sum
  Rancher.Desktop-1.16.0.aarch64.dmg

After:

stew i rancher-sandbox/rancher-desktop
rancher-sandbox/rancher-desktop
! Could not automatically detect the release asset matching your OS/Arch. Please select it manually:  [Use arrows to move, type to filter]
> Rancher.Desktop-1.16.0-mac.x86_64.zip
  Rancher.Desktop-1.16.0.x86_64.dmg

uname -a
Darwin m 24.0.0 Darwin Kernel Version 24.0.0: Tue Sep 24 23:37:13 PDT 2024; root:xnu-11215.1.12~1/RELEASE_ARM64_T8112 x86_64