Add conda-forge package

[candalfigomoro]

In addition to the pypi package, please add a conda-forge package (https://conda-forge.org).

I can give support if needed.

You can easily create a boilerplate conda recipe with grayskull (starting from the pypi package): https://github.com/conda-incubator/grayskull (note: the "annoy" package is called "python-annoy" in conda-forge).