Beta release 0.19.0b1

What's Changed

• Support polars DataFrames, LazyFrames by @cosmicBboy in #1373
• bugfix: optional columns in polars schema should no longer raise errors when not present by @cosmicBboy in #1532
• check_nullable does not uselessly compute isna() anymore in pandas backend by @smarie in #1538
• Polars LazyFrames are validated at the schema-level by default by @cosmicBboy in #1534
• Enable from_format_kwargs for dict format by @ektar in #1539
• Convert docs to myst by @cosmicBboy in #1542
• fix README(tab to space) by @np-yoe in #1544
• pandas DataFrameModel accepts python generic types by @cosmicBboy in #1547
• Backend registration happens at schema initialization by @cosmicBboy in #1548

New Contributors

• @smarie made their first contribution in #1538
• @ektar made their first contribution in #1539
• @np-yoe made their first contribution in #1544

Full Changelog: v0.18.3...v0.19.0b1