Polars: py-0.20.27 Release

[!WARNING]
This release was yanked. Please use the 0.20.28 release instead.

⚠️ Deprecations

• Change parameter chunked to allow_chunks in parametric testing strategies (#16264)

🚀 Performance improvements

• Use branchless uleb128 decoding for parquet (#16352)
• Reduce error bubbling in parquet hybrid_rle (#16348)
• use is_sorted in ewm_mean_by, deprecate check_sorted (#16335)
• Optimize is_sorted for numeric data (#16333)
• do not use pyo3-built (#16309)
• Faster bitpacking for Parquet writer (#16278)
• Improve Series.to_numpy performance for chunked Series that would otherwise be zero-copy (#16301)
• Further optimise initial polars import (#16308)
• Avoid importing ctypes.util in CPU check script if possible (#16307)
• Don't rechunk when converting DataFrame to numpy/ndarray (#16288)
• use zeroed vec in ewm_mean_by for sorted fastpath (#16265)

✨ Enhancements

• expose BooleanFunction in expr IR (#16355)
• Allow read_excel to handle bytes/BytesIO directly when using the "calamine" (fastexcel) engine (#16344)
• Raise when joining on the same keys twice (#16329)
• Don't require data to be sorted by by column in rolling_*_by operations (#16249)
• Support List types in Series.to_numpy (#16315)
• Add to_jax methods to support Jax Array export from DataFrame and Series (#16294)
• Enable generating data with time zones in parametric testing (#16298)
• Add struct.field expansion (regex, wildcard, columns) (#16320)
• Add new alpha, alphanumeric and digit selectors (#16310)
• Faster bitpacking for Parquet writer (#16278)
• Add require_all parameter to the by_name column selector (#15028)
• Start updating BytecodeParser for Python 3.13 (#16304)
• Add struct.with_fields (#16305)
• Handle implicit SQL string → temporal conversion in the BETWEEN clause (#16279)
• Expose string expression nodes to python (#16221)
• Add new index/range based selector cs.by_index, allow multiple indices for nth (#16217)
• Show warning if expressions are very deep (#16233)
• Fix some issues in parametric testing with nested dtypes (#16211)

🐞 Bug fixes

• pick a consistent order for the sort options in PyIR (#16350)
• Infer CSV schema as supertype of all files (#16349)
• Fix issue in parametric testing where excluded_dtypes list would grow indefinitely (#16340)
• Address overflow combining u64 hashes in Debug builds (#16323)
• Don't exclude explicitly named columns in group-by context' expr expansion (#16318)
• Improve map_elements typing (#16257)
• Harden Series.reshape against invalid parameters (#16281)
• Fix list.sum dtype for boolean (#16290)
• Don't stackoverflow on all/any horizontal (#16287)
• Fix Series.to_numpy for Array types with nulls and nested Arrays (#16230)
• `rolling_*_by was throwing incorrect error when dataframe was sorted by contained multiple chunks (#16247)
• Don't allow passing missing data to generalized ufuncs (#16198)
• Address overly-permissive expand_selectors function, minor fixes (#16250)
• Add missing support for parsing instantiated Object dtypes Object() (#16260)
• Reading CSV with low_memory gave no data (#16231)
• Add missing read_database overload (#16229)
• Fix a rounding error in parametric test datetimes generation (#16228)
• Fix some issues in parametric testing with nested dtypes (#16211)

📖 Documentation

• Add missing word in join docstring (#16299)
• document that month_start/month_end preserve the current time (#16293)
• Add example for separator parameter in pivot (#15957)

📦 Build system

• Fix allocator features (#16365)
• Update Rust nightly toolchain version (#16222)

🛠️ Other improvements

• Move DataFrame.to_numpy implementation to Rust side (#16354)
• Organize PyO3 NumPy code into interop::numpy module (#16346)
• simplify interpolate code, add test for rolling_*_by with nulls (#16334)
• Very minor refactor of DataFrame.to_numpy code (#16325)
• InterchangeDataFrame.version should be a ClassVar (not a property) (#16312)
• Add polars-expr README (#16316)
• Raise import timing test threshold (#16302)
• Use cls (not self) in classmethods (#16303)
• Use Scalar instead of Series some aggregations (#16277)
• Do not hardcode bash path in Makefile (#16263)
• Add IR::Reduce (not yet implemented) (#16216)
• move all describe, describe_tree and dot-viz code to IR instead of DslPlan (#16237)

Thank you to all our contributors for making this release possible! @MarcoGorelli, @NickCondron, @ShivMunagala, @alexander-beedie, @brandon-b-miller, @coastalwhite, @datenzauberai, @itamarst, @jsarbach, @max-muoto, @nameexhaustion, @orlp, @r-brink, @ritchie46, @stinodego, @thalassemia, @twoertwein and @wence-