tsconfig.json parser rejects TypeScript 2.1 and 2.2 options

[Jessidhia]

Example:

{
  "compilerOptions": {
    "target": "esnext",
    "module": "es2015",
    "moduleResolution": "node",
    "maxNodeModuleJsDepth": 1
  }
}

"target": "es2016" and "target": "es2017" are also supported options in 2.1 that are rejected by the parser. "target": "esnext" is added in 2.2.