Feature request: error out if using unsupported node when bootstrapping with --typescript

Created by: city41

Is your proposal related to a problem?

When using an unsupported version of node (in my case, 8.9.4), create-react-app will still bootstrap an app, but with a warning:

Note: the project was bootstrapped with an old unsupported version of tools.
Please update to Node >=8.10 and npm >=5 to get supported tools in new project

This is reasonable behavior. But my problem is if you pass the --typescript argument, the bootstrapped app will be JavaScript.

Describe the solution you'd like

If using an unsupported version of node and passing the --typescript argument, I'd like CRA to error out and refuse to bootstrap the app with a descriptive error message.

• it's pretty easy to miss the warning
• when you look at the built app, it's confusing and frustrating it is JavaScript instead of TypeScript without an obvious explanation (assuming you miss the warning)

My hunch is I must be using an old version of CRA. But this happens with the recent versions of CRA, making the result even more confusing.

Additional context

I am using CRA version 3.1.2

If the team agrees this is a good change, I'd be happy to take a stab at a PR on it.