remove unused onReady prop and update README.md (#247)

Co-authored-by: turtle <[email protected]>

Author: AmazingTurtle

README.md

@@ -58,7 +58,6 @@ React.render(<Upload />, container);
 |className | string | - | root component className |
 |disabled | boolean | false | whether disabled |
 |component | "div"|"span" | "span"| wrap component name |
-|onReady | function | | only call when supportServerRender is true, upload is rendered completely |
 |action| string &#124; function(file): string &#124; Promise&lt;string&gt; | | form action url |
 |method | string | post | request method |
 |directory| boolean | false | support upload whole directory |

src/Upload.jsx

@@ -13,7 +13,6 @@ class Upload extends Component {
     headers: {},
     name: 'file',
     multipart: false,
-    onReady: empty,
     onStart: empty,
     onError: empty,
     onSuccess: empty,
@@ -24,10 +23,6 @@ class Upload extends Component {
     openFileDialogOnClick: true,
   }
 
-  componentDidMount() {
-    this.props.onReady();
-  }
-
   abort(file) {
     this.uploader.abort(file);
   }