update readme

Author: wangzuo

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## 3.0.0
 
 - true alpha support with `initialValue`
+- remove `initialHexColor` support
 - set alpha 0 - 100
 
 ## 2.0.29

README.md

@@ -27,6 +27,8 @@ yarn add react-input-color
 
 ### Usage
 
+The `initialValue` property supports 6 (`#RRGGBB`) and 8 (`#RRGGBBAA`) digits hex value.
+
 ```javascript
 import React from 'react';
 import InputColor from 'react-input-color';

stories/InputColor.stories.js

@@ -22,10 +22,10 @@ export const Demo = () => {
           width: 50,
           height: 50,
           marginBottom: 20,
-          backgroundColor: color.hex
+          backgroundColor: color.rgba
         }}
       >
-        {color.hex}
+        {color.rgba}
       </div>
       <input
         type="color"