Add recipe for github/Bogdanp/py-test.el

I am the maintainer of this package. You can find it at https://github.com/Bogdanp/py-test.el .

From its description:

    py-test gives you the ability to define testing projects and, based
    on those projects, run a single test that's defined in the current
    buffer, all of the tests that you have defined in the current
    buffer, or all of the tests that you have defined in the current
    buffers's parent directory.

I've had to explicitly state which files are part of the package since files matching `*-test.el` are excluded by default.