migrate to API v3

[shcheklein]

V3 has nice features like an ability to fetch only the fields in JSON that you need.

Related not tested attempts to migrate: joapuiib/PyDrive@ab84389

[mozboz]

v2 to v3 changes reference doc: https://developers.google.com/drive/api/v2/v2-to-v3-reference

[efiop]

For the record: would reconsider in favor of improving https://github.com/intake/gdrivefs . At least for our (dvc) purposes.

[cristina0botez]

Hi! As far as I can tell, the library has not yet migrated to Google Drive API v3. Is there any progress on this?