🚀 Performance improvements

• improve streaming primitve groupby (#5575)
• vectorize integer vec-hash by using very simple, … (#5572)

✨ Enhancements

• prefer streaming groupby if partitionable (#5580)

🐞 Bug fixes

• fix ub due to invalid dtype on splitting dfs (#5579)

🛠️ Other improvements

• Remove old Python changelog file (#5577)
• namespace registration docs update (#5565)
• Improve contributing guide (#5558)

Thank you to all our contributors for making this release possible! @alexander-beedie, @ghuls, @ritchie46 and @stinodego