Bump handlebars from 4.1.2 to 4.6.0 (#1840)

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.1.2 to 4.6.0.
- [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...v4.6.0)

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

yarn.lock

@@ -4629,9 +4629,9 @@ gzip-size@^5.0.0, gzip-size@^5.1.1:
     pify "^4.0.1"
 
 handlebars@^4.1.2:
-  version "4.5.3"
-  resolved "https://registry.yarnpkg.com/handlebars/-/handlebars-4.5.3.tgz#5cf75bd8714f7605713511a56be7c349becb0482"
-  integrity sha512-3yPecJoJHK/4c6aZhSvxOyG4vJKDshV36VHp0iVCDVh7o9w2vwi3NSnL2MMPj3YdduqaBcu7cGbggJQM0br9xA==
+  version "4.6.0"
+  resolved "https://registry.yarnpkg.com/handlebars/-/handlebars-4.6.0.tgz#33af6c3eda930d7a924f5d8f1c6d8edc3180512e"
+  integrity sha512-i1ZUP7Qp2JdkMaFon2a+b0m5geE8Z4ZTLaGkgrObkEd+OkUKyRbRWw4KxuFCoHfdETSY1yf9/574eVoNSiK7pw==
   dependencies:
     neo-async "^2.6.0"
     optimist "^0.6.1"
@@ -8925,9 +8925,9 @@ typescript@next:
   integrity sha512-Vk/wZedTpVd3QAhr3mG1+sbUHcpJ1wfw49Wo1NCQvzMa0vHCJeocEwWzaV2yWprsuuFv4+e8tjCj1Vnme2CMHg==
 
 uglify-js@^3.1.4:
-  version "3.7.3"
-  resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.7.3.tgz#f918fce9182f466d5140f24bb0ff35c2d32dcc6a"
-  integrity sha512-7tINm46/3puUA4hCkKYo4Xdts+JDaVC9ZPRcG8Xw9R4nhO/gZgUM3TENq8IF4Vatk8qCig4MzP/c8G4u2BkVQg==
+  version "3.7.4"
+  resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.7.4.tgz#e6d83a1aa32ff448bd1679359ab13d8db0fe0743"
+  integrity sha512-tinYWE8X1QfCHxS1lBS8yiDekyhSXOO6R66yNOCdUJeojxxw+PX2BHAz/BWyW7PQ7pkiWVxJfIEbiDxyLWvUGg==
   dependencies:
     commander "~2.20.3"
     source-map "~0.6.1"