Added missing Image clipPath property to type def.

In the specs can be found that this property may be used, and I have verified the working;
https://github.com/react-native-community/react-native-svg#image

index.d.ts

@@ -225,6 +225,7 @@ export interface ImageProps extends ResponderProps, CommonMaskProps, ClipProps,
   href: ReactNative.ImageProperties['source'],
   preserveAspectRatio?: string,
   opacity?: NumberProp,
+  clipPath?: string
 }
 export const Image: React.ComponentClass<ImageProps>;