v0.4.0: Added some icons and cumulative updates

⚠️ BREAKING CHANGES

• f9bf762: improved the icons
  • This update unifies the origin position of icons.
    As a result, some icons are larger in apparent size.
• 825eea3: renamed the user icon
  • User -> UserIcon
  • This is usually not a problem since the GUIDs are identical.
    Still, it is a destructive change if used outside of Unity.

Features

• cc4a34a: added the 16 icons
  • The total number of icons is now 80.
• 826be8f: improved the icons gallery scene for example

CI / CD

• 2ba1882: added the signing with GPG
• 39cf905: add version detection for prerelease in the release workflow
• 5893feb: added the declaration of the dynamic variables
• 2472b55: added the ImgBot configuration

Other updates

• c6078c9: improved the manifest configuration
• c36c58d: updated the dependencies
• 25fa177: bumped the version number

Chores

• d81f72f: fixed the problem that the pre-placement templates appear to have syntax errors
• cddfa3c: fixed the wrong configuration of the ASDF
• f2d4a73: linted

See also

• #8