Bump handlebars from 4.1.2 to 4.3.0 (#1118)

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.1.2 to 4.3.0.
- [Release notes](https://github.com/wycats/handlebars.js/releases)
- [Changelog](https://github.com/wycats/handlebars.js/blob/master/release-notes.md)
- [Commits](handlebars-lang/handlebars.js@v4.1.2...v4.3.0)

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

package.json

@@ -42,7 +42,7 @@
     "eslint-plugin-standard": "^4.0.0",
     "file-loader": "^2.0.0",
     "flex.less": "^1.1.0",
-    "handlebars": "^4.1.2",
+    "handlebars": "^4.3.0",
     "handlebars-loader": "^1.7.0",
     "highlight.js": "9.11.x",
     "jquery": "^3.4.0",