Changed python binding classifier

[AlvinMooreSr]

Replaced python binding classifier within configuration file to one that is acceptable by pypi listed at https://pypi.org/pypi?%3Aaction=list_classifiers

[alexmiller-apple]

Note that there's a lot of conversation on the topic of the lack of specifically apache v2 in pypa/pypi-legacy #91 and pypa/warehouse #2996.

[davelester]

+1, thanks @AlvinMooreSr!

PyPI describes the use of classifiers, and says they can "be used by community members to find projects based on their desired criteria." Sounds like their function is essentially for discovery of repos.

With that in mind, this change looks good and ready to merge with a few minor caveats if this PR is ever revisited:

1. the LICENSE file in the project root and license headers on individual Python binding files should remain Apache v2
2. when a more-descriptive classifier exists, let's make a point to update FDB to properly reflect the specific license version [I've subscribed to pypa/warehouse #2996, but if anyone else wants to help monitor its progress and follow-up here, I'd appreciate it]