upload file and got cast error

Upload file to server and got cast error in file widget.dart @jonataslaw

Error is
`_CastError (type 'Future?>' is not a subtype of type 'FutureOr>' in type cast)`

Function is
```
@override
Future file(String name, {Encoding encoder = utf8}) async {
final payload = await (request.payload(encoder: encoder)
as FutureOr>);
final multiPart = await payload[name];
if (multiPart is MultipartUpload) {
return multiPart;
} else {
Get.log('Incorrect format, upload the file as Multipart/formdata',
isError: true);
return MultipartUpload(null, null, null, null);
}
}
```

Maybe we should wrap function's body with try..catch as below.
```
@override
Future file(String name, {Encoding encoder = utf8}) async {
try {
final payload = await (request.payload(encoder: encoder)
as FutureOr?>);

final multiPart = await payload![name];
if (multiPart is MultipartUpload) {
return multiPart;
} else {
Get.log('Incorrect format, upload the file as Multipart/formdata',
isError: true);
return MultipartUpload(null, null, null, null);
}
} catch (e) {
return MultipartUpload(null, null, null, null);
}
}
```
// I love get_server,It's Great!