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)

---
updated-dependencies:
- dependency-name: handlebars
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>