(types): canvasProps should be more specific than any

- not sure if <object> makes sense, but it needed an argument

Author: agilgur5

src/index.d.ts

@@ -16,7 +16,7 @@ export interface IOptions {
 
 // props specific to the React wrapper
 export interface SignatureCanvasProps extends IOptions {
-  canvasProps?: any,
+  canvasProps?: React.CanvasHTMLAttributes<object>,
   clearOnResize?: boolean
 }