Bump generator-jhipster from 4.14.0 to 6.3.1

Bumps [generator-jhipster](https://github.com/jhipster/generator-jhipster) from 4.14.0 to 6.3.1.
- [Release notes](https://github.com/jhipster/generator-jhipster/releases)
- [Commits](jhipster/generator-jhipster@v4.14.0...v6.3.1)

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

package.json

@@ -50,7 +50,7 @@
     "extract-text-webpack-plugin": "4.0.0-beta.0",
     "file-loader": "1.1.11",
     "fork-ts-checker-webpack-plugin": "0.4.2",
-    "generator-jhipster": "4.14.0",
+    "generator-jhipster": "6.3.1",
     "html-loader": "0.5.5",
     "html-webpack-plugin": "3.0.6",
     "husky": "0.14.3",