Polars: py-0.20.15 Release

🚀 Performance improvements

• Ensure parallel encoding/compression in sink_parquet (#14964)
• hoist errors out of iterators in parquet (#14945)
• add basic AVX-512 filters (#14892)

✨ Enhancements

• Support writing Array type in parquet (#14943)
• Add drop_first parameter to Series.to_dummies (#14846)
• Add "execute_options" support for read_database_uri (#14682)

🐞 Bug fixes

• Fix invalid paritionable query (#14966)
• allow nonstrict cast of categorical/enum to enum (#14910)
• count_rows multi-threaded under-counting in parser.rs (#14963)
• raise proper error instead of panicking when result of truncation is non-existent datetime (#14958)
• ooc-sort issues (#14959)
• Do not raise when constructing from a list of Series with Nones (#14942)
• Don't access out-of-bounds for null indices in bitmap gather (#14932)
• std when ddof>=n_values returns None even in rolling context (#11750)
• Don't rechunk categoricals when moving to physical (#14934)
• Ensure consistent read_database behaviour with empty ODBC "iter_batches" (#14918)
• parquet rle boolean decoder (#14931)
• Fix frame init from single RecordBatch objects when pyarrow <= 12 (#14922)
• boolean filter gave overly large buffers to Bitmap::from_u8_vec (#14924)
• Fix sliced dictionary state in parquet (#14917)
• read_database now properly handles empty result sets from arrow-odbc (#14916)
• Fix possibly incorrect order of columns when using ipc stream with_columns (#14859)

📖 Documentation

• Add note about include_index in from_pandas regarding "default indices" (#14920)
• Remove some repetition in comments/docstrings (#14912)

🛠️ Other improvements

• Update Cargo.lock and remove cmake limit workaround (#14905)
• Simplify streaming placeholder replacement. (#14915)
• Optional deps should include fastexcel (#14907)
• Deduplicate POLARS_FORCE_ASYNC env var parsing (#14909)

Thank you to all our contributors for making this release possible! @MarcoGorelli, @alexander-beedie, @ambidextrous, @battmdpkq, @mcrumiller, @mickvangelderen, @orlp, @petrosbar and @ritchie46