v0.3.12 Upgrade arrow-rs and bug fixes

• Upgraded arrow-rs dependency to 33.0 (Waiting on datafusion for 34.0 upgrade).
• Nested Dictionary fields are now parsed and written correctly.
• More progress towards OPQ implementation.

What's Changed

• Matrix mul and transpose by @eddyxu in #661
• Recursively set dictionaries in struct fields by @gsilvestrin in #662
• Upgrading arrow version to 33.0 by @gsilvestrin in #665
• [Rust] sampling over matrix. by @eddyxu in #666
• Sorting dataset versions by @gsilvestrin in #668

Full Changelog: v0.3.11...v0.3.12