Release 2.12.1

See https://docs.lamin.ai/changelog#db-2-12-1

What's Changed

• 📝 Improve storage docs by @falexwolf in #4027
• 🚸 Clean up code base and remove long-deprecated API calls by @falexwolf in #4028
• 📝 README v5.12: Add sharded datasets by @falexwolf in #4029
• 🐛 Validate nullable feature values prior to dropping them for writes in Record() by @AllaVinner in #4033
• 🐛 Fix schema.describe() if itype is a feature subtype by @falexwolf in #4031
• 🐛 Include required nullable features in record.features.get_values() by @AllaVinner in #4032

Full Changelog: 2.12.0...2.12.1