build(deps): update yeoman-generator requirement from ^3.1.1 to ^4.0.0 (#152)

Updates the requirements on [yeoman-generator](https://github.com/yeoman/generator) to permit the latest version.
- [Release notes](https://github.com/yeoman/generator/releases)
- [Commits](https://github.com/yeoman/generator/compare/v3.1.1...v4.0.0)

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

superset-frontend/temporary_superset_ui/superset-ui/packages/generator-superset/package.json

@@ -31,7 +31,7 @@
   "dependencies": {
     "chalk": "^2.4.1",
     "lodash": "^4.17.11",
-    "yeoman-generator": "^3.1.1",
+    "yeoman-generator": "^4.0.0",
     "yosay": "^2.0.2"
   },
   "license": "Apache-2.0",