@types into devDependencies

In a new project all @types in the devDependencies. So the install command should also add them there

Author: StefanSchoof

Diff for: packages/react-scripts/template/README.md

@@ -1264,13 +1264,13 @@ When you encounter bugs caused by changing components, you will gain a deeper in
 If you’d like to test components in isolation from the child components they render, we recommend using [`shallow()` rendering API](http://airbnb.io/enzyme/docs/api/shallow.html) from [Enzyme](http://airbnb.io/enzyme/). To install it, run:
 
 ```sh
-npm install --save enzyme @types/enzyme enzyme-adapter-react-16 @types/enzyme-adapter-react-16 react-test-renderer @types/react-test-renderer
+npm install --save-dev enzyme @types/enzyme enzyme-adapter-react-16 @types/enzyme-adapter-react-16 react-test-renderer @types/react-test-renderer
 ```
 
 Alternatively you may use `yarn`:
 
 ```sh
-yarn add enzyme @types/enzyme enzyme-adapter-react-16 @types/enzyme-adapter-react-16 react-test-renderer @types/react-test-renderer
+yarn add --dev enzyme @types/enzyme enzyme-adapter-react-16 @types/enzyme-adapter-react-16 react-test-renderer @types/react-test-renderer
 ```
 
 As of Enzyme 3, you will need to install Enzyme along with an Adapter corresponding to the version of React you are using. (The examples above use the adapter for React 16.)