dogwrap cannot choose the US3 site.

[holidayworking]

Describe the bug
I need to send data to the US3 site, but dogwrap cannot choose the US3 site.

$ dogwrap -n test -s us3 "ls"
Usage: dogwrap -n [event_name] -k [api_key] --submit_mode [ all | errors | warnings] [options] "command".

Note that you need to enclose your command in quotes to prevent python executing as soon as there is a space in your command.

NOTICE: In normal mode, the whole stderr is printed before stdout, in flush_live mode they will be mixed but there is not guarantee that messages sent by the command on both stderr and stdout are printed in the order they were sent.

dogwrap: error: option -s: invalid choice: 'us3' (choose from 'datadoghq.com', 'us', 'datadoghq.eu', 'eu')

To Reproduce
Steps to reproduce the behavior:

1. Choose the US3 site when you sign up.
2. Run this command.

$ dogwrap -n test -s us3 "ls"

Expected behavior
dogwrap can choose the US3 site.

Environment and Versions (please complete the following information):

$ dogwrap --version
dogwrap 0.44.0