Expose dropFileRemoveButton styles in style interface

[seans84]

Here: https://github.com/Bunlong/react-papaparse/blob/master/src/CSVReader.tsx#L442 and https://github.com/Bunlong/react-papaparse/blob/master/src/CSVReader.tsx#L456 can you expose the option to pass in dropFileRemoveButton styling from the styles config?

I would like to position the remove button differently, but currently it is impossible to access it.

Something like this I think would work fine:

style={style.dropFileRemoveButton || styles.dropFileRemoveButton}

[TimJJTing]

Also need this feature!