Git-up

- Include tests in PyPI distribution (51).

- 3rd party dependencies have been updated.
- Dependencies on 3rd party libraries have been loosened to better interact with other installed packages. Thanks [MaximilianR](https://github.com/MaximilianR) for the [Pull Request](https://github.com/msiemens/PyGitUp/pull/45).
- Added an command line argument to turn of fetching (`--no-fetch`). Thanks [buoto](https://github.com/buoto) for the [Pull Request](https://github.com/msiemens/PyGitUp/pull/46).
- Don’t show a stacktrace anymore when stashing fails ([35](https://github.com/msiemens/PyGitUp/issues/35)).
- Fixed a bug that cuased problems with submodules if the submodule had unstashed changes/ Thanks [Javex](https://github.com/Javex) for the [Pull Request](https://github.com/msiemens/PyGitUp/pull/27).

- Fixed a bug when showing the version on Python 3 (34).

- Support for Python 3 has been added. Thanks r4ts0n for the
[Pull Request](https://github.com/msiemens/PyGitUp/pull/23) and Byron for quickly merging a Pull Request
in [GitPython](https://github.com/gitpython-developers/GitPython) and releasing a new version on which this release
depends.

- Now updates submodules when called from `git submodule foreach` (8).

- Fixed a problem with `setuptools 8.x` (19).
- 3rd party dependencies have been updated