0.3.9 Hotfix 1 - fixing optional dependencies

We forgot to expose the optional dependencies in the previous release. This release should fix that issue

What's Changed

• Add function to get the client for the S3 Repo Bucket by @kbolashev in #387
• Pass extras_require in setup.py by @kbolashev in #392

Full Changelog: 0.3.9...0.3.9_1