Release DataFusion `56.0.0` (Oct 2026)

[alamb]

Is your feature request related to a problem or challenge?

• Part of [EPIC] DataFusion Releases #19783

Previous release is #22393 (Jul / Aug 2026) so next major release would be approximately Sep / Oct 2026.

Steps:

• Create a branch-56 branch
• Update version and changelog
• Test with DataFusion Python
• Test with DataFusion Comet
• Test with DataFusion Ballista
• Test with delta.rs
• Test vortex
• Test with iceberg-rust
• Test with LakeSail
• Test with parquet viewer
• Test with datafusion-materialized-views
• Voting Thread
• Publish to crates.io
• Create ticket for next release: Release DataFusion 56.1.0 (minor/patch) Release (Nov 2026) #24463
• Create blog post

Features to mention in the blog (if they make it)

• ASOF joins from @Xuanwo : ASOF join support / Specialize Range Joins #318

Bugs that should be fixed

• TBD

Community Wishlist

• TBD