Install husky, lint-staged, and prettier to dev deps

[dankreiger]

• A small fix

I really like using husky, lint-staged, and prettier with create-react-app.

I don't see why they should be included in the production bundle though, so I just updated the docs accordingly to make sure people install them as dev dependencies.

[rovansteen]

Unless you somehow require them in your source files they won’t end up in the production bundle though.

[dankreiger]

@rovansteen I see. If nothing else it makes sure package.json remains organized. Should I close this then?

The only other thing I'd say is that the official docs from all 3 of these dependencies instruct us to use npm install --save-dev or yarn add --dev

https://github.com/typicode/husky#install
https://github.com/okonet/lint-staged#installation-and-setup
https://prettier.io/docs/en/install.html

[stramel]

A nice benefit of them being in the devDeps is that using a production install command won't waste time installing them. It can help keep docker images smaller.

[bugzpodder]

@dankreiger thanks for the PR. Please see #3209 on reasons on why the docs doesn't suggest dev dependencies.