message: chore(package): downgrade typescript version
  * Downgrades lowest possible version to 2.3 because of angular 4
  incompatibility with typesscript>=2.4.0, closes
diff: "@angular/compiler": ">=4.3.0",
  "@angular/core": ">=4.3.0",
  "@angular/forms": ">=4.3.0",
  - "typescript": ">=2.4.2",
  + "typescript": ">=2.3.0",
  "rxjs": ">=5.4.3"
  },
  "devDependencies": {
  