FileUpload - Types changed after react-dropzone upgrade

[nicolethoen]

Follow up to breaking change PR [link]

I'm not positive if we can do anything here other than warn consumers of FileUpload that props they are using have had types updated.

The prop types of FileUpload's onFileInputChange prop and dropzoneProps prop have been updated.
The prop types of MultipleFileUpload's dropzoneProps prop has been updated.

Required actions:

1. Build codemod
2. Build test
3. Update readme with description & example