Add changelog for 0.2.3

Created by: gaearon

0.2.3 (August 25, 2016)

Build Dependency (react-scripts)

• You can now proxy requests to an API server without worrying about CORS. (@gaearon in #282)
• You can now pass custom environment variables to your application. (@eliperelman in #342)
• You can now use async and await syntax. (@gaearon in #327, @fson in #332)
• Paths with period in them now load successfully on the development server. (@mxstbr in #422)
• Images with .webp extension are now supported. (@gafemoyano in #458)
• The most recent version of React is now added to package.json. (@wdhorton in #477)
• Babel configuration is simplified. (@kripod in #490)

Migrating from 0.2.2 to 0.2.3

Update react-scripts to point to 0.2.3 in your package.json and run npm install. You shouldn’t need to do anything else.

Newly created projects will use 0.2.3 automatically. You don’t need to update the global create-react-app CLI itself. It stays at 0.2.0 for now because it doesn’t have any changes.