OpenThings v0.4.0

What's Changed

• Docs: how to use Siri and Shortcuts on iPhone by @spuder in #51
• Desktop CI: run the Arch Linux work as three parallel jobs by @spuder in #50
• Repeating to-dos: a repeat editor, and richer rules by @spuder in #52
• Add Nix flake: desktop app and server for Linux and macOS (x86_64 + aarch64) by @spuder in #27
• Move to Trash takes the to-do off the list right away by @spuder in #57
• Release v0.4.0 by @spuder in #60

Full Changelog: v0.3.0...v0.4.0