Bump ember-cli-fastboot from 4.1.4 to 4.1.5 (#898)

Bumps [ember-cli-fastboot](https://github.com/ember-fastboot/ember-cli-fastboot) from 4.1.4 to 4.1.5.
- [Release notes](https://github.com/ember-fastboot/ember-cli-fastboot/releases)
- [Changelog](https://github.com/ember-fastboot/ember-cli-fastboot/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ember-fastboot/ember-cli-fastboot/commits)

---
updated-dependencies:
- dependency-name: ember-cli-fastboot
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>