Show a message when using the cli with a wrong option

[cricrio]

I try to start my project with gatsby create my-blog in place of gatsby new my-blog.
When we use the cli with a wrong argument it does nothing.
I think it should be better if the cli throws an error message or shows the different options.

[KyleAMathews]

Great suggestion! This would need added here: https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-cli/src/create-cli.js

[KyleAMathews]

Would love a PR from you @cricrio if you could look into it or anyone else who'd like to jump on this nice UX improvement.

[cricrio]

Nice to hear that! I will try to do it.

[tsriram]

Closed with #3668