build(deps): update handlebars requirement from 5 to 6

Updates the requirements on [handlebars](https://github.com/sunng87/handlebars-rust) to permit the latest version.
- [Release notes](https://github.com/sunng87/handlebars-rust/releases)
- [Changelog](https://github.com/sunng87/handlebars-rust/blob/master/CHANGELOG.md)
- [Commits](sunng87/handlebars-rust@v5.0.0...v6.0.0)

---
updated-dependencies:
- dependency-name: handlebars
  dependency-type: direct:production
...

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

generator/Cargo.toml

@@ -14,7 +14,7 @@ anyhow = "1.0"
 clap = { version = "4", features = ["derive"] }
 cruet = "0.14"
 glob = "0.3"
-handlebars = { version = "5", features = ["dir_source"] }
+handlebars = { version = "6", features = ["dir_source"] }
 handlebars_misc_helpers = { version = "0.16", default-features = false, features = [
   "string",
   "json",