buggy recommendation for version param in json config traitlets/docs/source/config.rst

[GaryHendrick]

in reading the doc traitlets/docs/source/config.rst the json configuration example includes the following,
which will result in a ValueError raised within JSONFileConfigLoader._convert_to_config(self, dictionary), because of the version parameter value "1.0"

  "version": "1.0",
  "MyClass": {
    "name": "coolname",
    "ranking": 10
  }
}

The ValueError is raised because "1.0" is not equal to 1, as checked in _convert_to_config
This can be recreated by creating the example's json config file and load_config_file for that file, on
an Application from the module traitlets.config.application

You should see

...
  File "<decorator-gen-5>", line 2, in load_config_file
  File "D:\usr\local\Anaconda3\envs\opencv_tutorials\lib\site-packages\traitlets\config\application.py", line 87, in catch_config_error
    return method(app, *args, **kwargs)
  File "D:\usr\local\Anaconda3\envs\opencv_tutorials\lib\site-packages\traitlets\config\application.py", line 598, in load_config_file
    raise_config_file_errors=self.raise_config_file_errors,
  File "D:\usr\local\Anaconda3\envs\opencv_tutorials\lib\site-packages\traitlets\config\application.py", line 562, in _load_config_files
    config = loader.load_config()
  File "D:\usr\local\Anaconda3\envs\opencv_tutorials\lib\site-packages\traitlets\config\loader.py", line 407, in load_config
    self.config = self._convert_to_config(dct)
  File "D:\usr\local\Anaconda3\envs\opencv_tutorials\lib\site-packages\traitlets\config\loader.py", line 423, in _convert_to_config
    raise ValueError('Unknown version of JSON config file: {version}'.format(version=version))
ValueError: Unknown version of JSON config file: 1.0

{'commit_hash': '51ce9d73b',
 'commit_source': 'installation',
 'default_encoding': 'utf-8',
 'ipython_path': 'D:\\usr\\local\\Anaconda3\\envs\\opencv_tutorials\\lib\\site-packages\\IPython',
 'ipython_version': '6.0.0',
 'os_name': 'nt',
 'platform': 'Windows-10-10.0.15063-SP0',
 'sys_executable': 'D:\\usr\\local\\Anaconda3\\envs\\opencv_tutorials\\python.exe',
 'sys_platform': 'win32',
 'sys_version': '3.6.1 | packaged by conda-forge | (default, May 11 2017, '
                '19:39:41) [MSC v.1900 64 bit (AMD64)]'}

[minrk]

Thanks! doc fixed