devel/py-b2: Update to 4.4.1

Adjust some dependencies.

Changes since 4.3.3:

• Pin docutils version to avoid breaking the dependent rst2ansi library.
• Migrate to b2sdk.v3
• Switched to cloud-based signing using DigiCert KeyLocker.
• Add multi-bucket keys support to the key create subcommand.
• Support multi-bucket keys in key list subcommand.

Reported by: github