Bump ember-cli-htmlbars from 4.3.1 to 5.1.2

Bumps [ember-cli-htmlbars](https://github.com/ember-cli/ember-cli-htmlbars) from 4.3.1 to 5.1.2.
- [Release notes](https://github.com/ember-cli/ember-cli-htmlbars/releases)
- [Changelog](https://github.com/ember-cli/ember-cli-htmlbars/blob/master/CHANGELOG.md)
- [Commits](ember-cli/ember-cli-htmlbars@v4.3.1...v5.1.2)

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

Author: dependabot-preview[bot]