saturnus 0.8.1

saturnus 0.8.1 brings the desktop app to ARM: Windows on ARM and Linux
aarch64 now have their own installers. Nothing else changes; see 0.8.0
for this week's new features.

Get it

• On the web, nothing to install: https://ractive.ch/saturnus/app/
  (Chrome or Edge for a serial cable; every browser for the emulated
  calculator).
• The desktop app saturnus_0.8.1_… (on Linux saturnus-app), with a
  -SHA256SUMS file beside them:
  • macOS, Apple silicon: .dmg, signed and notarised, or brew trust --cask ractive/tap/saturnus-app once, then brew install --cask ractive/tap/saturnus-app;
  • Windows: .msi or -setup.exe for x86_64 (x64) and, new, for ARM
    (arm64);
  • Linux: .deb, .rpm or .AppImage for x86_64 (amd64, x86_64)
    and, new, for ARM (arm64, aarch64). Add yourself to the dialout
    group to use a serial port.
• The command-line tools saturnus and satx: cargo install,
  Homebrew ractive/tap, Scoop ractive, or the archives and Linux
  packages below (ARM archives as before).
• Libraries on crates.io, all at 0.8.1, unchanged apart from the
  version.

Desktop app on ARM

• Windows on ARM runs the app natively. The setup .exe itself is the
  usual installer, which Windows runs emulated; the app it installs is
  ARM.
• Linux aarch64 gets the same three packages as x86_64, the package
  saturnus-app.