Bump @tootallnate/once and electron-builder

Removes [@tootallnate/once](https://github.com/TooTallNate/once). It's no longer used after updating ancestor dependency [electron-builder](https://github.com/electron-userland/electron-builder/tree/HEAD/packages/electron-builder). These dependencies need to be updated together.


Removes `@tootallnate/once`

Updates `electron-builder` from 25.1.8 to 26.8.1
- [Release notes](https://github.com/electron-userland/electron-builder/releases)
- [Changelog](https://github.com/electron-userland/electron-builder/blob/master/packages/electron-builder/CHANGELOG.md)
- [Commits](https://github.com/electron-userland/electron-builder/commits/electron-builder@26.8.1/packages/electron-builder)

---
updated-dependencies:
- dependency-name: "@tootallnate/once"
  dependency-version: 
  dependency-type: indirect
- dependency-name: electron-builder
  dependency-version: 26.8.1
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]