uploaddocument missing service

[prakashkumar163]

Please include this feature also in this current python library
soap_url = "https://gateway.fedex.com:443/web-services/uploaddocument"
soap_url = "https://gatewaybeta.fedex.com:443/web-services/uploaddocument"

[radzhome]

I don't use that service, but if you get a chance, send a PR for this additional service.

[prakashkumar163]

@radzhome PR submitted, please do the needful.