Bump handlebars from 4.5.3 to 4.7.7

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.5.3 to 4.7.7. - [Release notes](https://github.com/wycats/handlebars.js/releases) - [Changelog](https://github.com/handlebars-lang/handlebars.js/blob/master/release-notes.md) - [Commits](handlebars-lang/handlebars.js@v4.5.3...v4.7.7) Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]