Bump tar and dmg-builder in /build

Bumps [tar](https://github.com/isaacs/node-tar) to 7.5.7 and updates ancestor dependency [dmg-builder](https://github.com/electron-userland/electron-builder/tree/HEAD/packages/dmg-builder). These dependencies need to be updated together.


Updates `tar` from 6.2.1 to 7.5.7
- [Release notes](https://github.com/isaacs/node-tar/releases)
- [Changelog](https://github.com/isaacs/node-tar/blob/main/CHANGELOG.md)
- [Commits](isaacs/node-tar@v6.2.1...v7.5.7)

Updates `dmg-builder` from 26.5.0 to 26.6.0
- [Release notes](https://github.com/electron-userland/electron-builder/releases)
- [Changelog](https://github.com/electron-userland/electron-builder/blob/master/packages/dmg-builder/CHANGELOG.md)
- [Commits](https://github.com/electron-userland/electron-builder/commits/electron-builder@26.6.0/packages/dmg-builder)

---
updated-dependencies:
- dependency-name: tar
  dependency-version: 7.5.7
  dependency-type: indirect
- dependency-name: dmg-builder
  dependency-version: 26.6.0
  dependency-type: direct:development
...

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Author: dependabot[bot]