v0.3.1 Index creation tool

We added an index creation tool that's 2x faster than FAISS.
Accessible in python via Dataset.create_index

What's Changed

• Add unit test for Dataset::take_rows by @eddyxu in #523
• Create index API from Python by @eddyxu in #524
• Implement a kmean optimized for Arrow-backed vectors in pure rust. by @eddyxu in #525
• Reimplement IVF_PQ index. by @eddyxu in #519
• Use pure rust kmean in IVF and PQ by @eddyxu in #526
• update release actions by @changhiskhan in #527
• [rust] make scanning in order configurable by @changhiskhan in #528

Full Changelog: v0.3.0...v0.3.1