What's Changed
* Integrate codspeed, 332
* add s390x & ppc64le linux binaries, 333
* switch `flake8` -> `ruff`, 334
* Improve PyMapping related function by tushushu in 314
* Enable CodSpeed tokenless uploads by art049 in 335
* Upgrade maturin to 0.14 by messense in 336
* Fix the Compile time RNG seed when running the benchmarks by art049 in 338
* Upgrade pytest-codspeed to 1.2.0 by art049 in 337
* Implement `LaxOrStrictValidator`, 330
* Investigate seg. faults with PyPy on CI, 341
* disable coverage on CI with PyPy, 344
* Implement datetime timezone constraints by antonagestam in 343
* Uprev linting, 346
* add `strip = true` to release profile, 348
* update pyodide to 0.22.0 by messense in 351
* Serialization, 327
* add docstrings and docstring tests by philhchen in 350
* Upgrade pyo3 to 0.18.0 by messense in 361
* Add python bindings for constructors for Url and MultiHostUrl by philhchen in 349
* utf8 error fixed on pypy with pyo3 0.18, 364
* try `mimalloc/local_dynamic_tls`, 363
* Support `kwargs` with `from_attributes` by jcsho in 306
* Test on other OSs, remove CI benchmarks, 366
* feat: remove usage of nohash_hasher in favor of ahash by czotomo in 360
* Union Serialization, 357
* rename 'new-class' and similar to 'model' by czotomo in 368
* add build tests on ppc64le, simplify, 369
* Serialize improvements, 370
* fix `is_enum`, 373
* general `to_json` method and more inferred types, 372
New Contributors
* tushushu made their first contribution in 314
* art049 made their first contribution in 335
* antonagestam made their first contribution in 343
* philhchen made their first contribution in 350
* jcsho made their first contribution in 306
**Full Changelog**: https://github.com/pydantic/pydantic-core/compare/v0.7.1...v0.8.1