Bump electron-builder from 26.5.0 to 26.8.1

Bumps [electron-builder](https://github.com/electron-userland/electron-builder/tree/HEAD/packages/electron-builder) from 26.5.0 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: electron-builder
  dependency-version: 26.8.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]