Ujenkins

- build.get() new args support (https://github.com/pbelskiy/ujenkins/pull/18)
- minor fixes

pin version of urllib2

[pin urllib3<2 to prevent error](https://github.com/pbelskiy/ujenkins/commit/382684dc89549fc25403f7b3de3f63f2ac7273ed)

https://github.com/pbelskiy/ujenkins/issues/15

- add build.get_artifact()

- fixed https://github.com/pbelskiy/ujenkins/issues/12

- update supported versions if Python on PyPI