Don't include tests in package

[languitar]

Currently the Python package generated by this project includes the test files under the very generic package name tests. This easily conflicts with other packages and pollutes the Python package namespace.

The Archlinux AUR package has just included a patch for this purpose. Would be nice if this was included here: https://aur.archlinux.org/cgit/aur.git/tree/exclude-tests.patch?h=awslogs&id=1c9beb4658f4a3824343a2249f0798aa0df37e40