refactor: bump @saithodev/semantic-release-backmerge from 2.1.2 to 4.0.1

Bumps [@saithodev/semantic-release-backmerge](https://github.com/saitho/semantic-release-backmerge) from 2.1.2 to 4.0.1.
- [Release notes](https://github.com/saitho/semantic-release-backmerge/releases)
- [Changelog](https://github.com/saitho/semantic-release-backmerge/blob/master/CHANGELOG.md)
- [Commits](saitho/semantic-release-backmerge@v2.1.2...v4.0.1)

---
updated-dependencies:
- dependency-name: "@saithodev/semantic-release-backmerge"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>