add support for windows in build and distribution of v2. If pywin is used, use `pywin32 >= 300` (ref: https://github.com/mhammond/pywin32/releases/tag/b300) _Originally posted by @sarasafavi in https://github.com/planetlabs/planet-client-python/pull/260#discussion_r600506995_