React: [Documentation] Add version information

[kyamaguchi81]

Please list [You’ll need to have Node >= 6 on your machine.]
before the description in [npm install -g create-react-app],
In [Creating a New Application] of the document https://facebook.github.io/react/docs/installation.html.

Because you want to know the required version before running the command

[gaearon]

If you run it with Node 4, it will use the last version of scripts that supported Node 4:

> create-react-app test123

Creating a new React app in /Users/dan/test123.

You are using Node v4.0.0 so the project will be boostrapped with an old unsupported version of tools.

Please update to Node 6 or higher for a better, fully supported experience.

[...]

Does this notice appear for you?

I think it’s fair to say you can still use it with Node 4, although the result will be an outdated version.

[gaearon]

Happy to take a PR adding the note though.

[kyamaguchi81]

I think it’s fair to say you can still use it with Node 4, although the result will be an outdated version.

I think it's good.

Happy to take a PR adding the note though.

I will make a pull request from next time.

Thank you.

[bvaughn]

Thank you for filing this issue! 😄

The documentation and source code for reactjs.org now lives in a different repository: reactjs/reactjs.org. (For more info on why we made this move, see issue #11075.)

I've moved your issue to the new repo: reactjs/reactjs.org#70

Let's continue the discussion there! Sorry for the inconvenience.