Suggestion - add a __version__ to annoy

[nlathia]

👋 Hey folks, I was hoping to use annoy.__version__ to check which version of the Python Annoy library someone is using when uploading a model using modelstore. It doesn't appear to be supported and throws an AttributeError.

>>> import annoy
>>> annoy.__version__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'annoy' has no attribute '__version__'

For now I'm falling back on one of the the (less common) approaches suggested here. If there's some scope to add that in (in the future), it would be great!

>>> import pkg_resources
>>> pkg_resources.get_distribution('annoy')
annoy 1.17.0 (/long/path/to/lib/python3.8/site-packages)
>>> pkg_resources.get_distribution('annoy').version
'1.17.0'