Polars: rs-0.39.2 Release

🚀 Performance improvements

• use two binary searches for equality mask when data is sorted (#15702)
• improve filter parallelism (#15686)

✨ Enhancements

• Remove outdated join validation checks (#15701)

🐞 Bug fixes

• manual cache (#15711)
• Ensure we don't hold onto Mutex when grabbing join tuples (#15704)
• allow null dtypes in UDFs if they match the schema (#15699)
• Respect join_null argument for semi/anti joins (#15696)
• Ensure we don't hold RwLock when spawning group parallelism in w… (#15697)
• Ensure empty with_columns is a no-op (#15694)
• Include predicate in cache state union (#15693)
• Add the missing feature flag for ewm_mean_by (#15687)
• 8/16-bits int could also apply in place for log expr (#15680)
• prepare_expression_for_context shouldn't panic if exceptions raised from optimizer (#15681)

🛠️ Other improvements

• Make json_path_match expr non-anonymous (#15682)

Thank you to all our contributors for making this release possible! @henryharbeck, @kszlim, @orlp, @reswqa and @ritchie46