[Python] Release 0.49.0

Added

• Validation of recursive Python objects. #945
• EXPERIMENTAL: Schema canonicalization via jsonschema::canonicalize. It reduces a reasonable subset of JSON Schemas to their normal forms.

Fixed

• multipleOf incorrectly accepted integers past u64 that are not multiples of the divisor.
• list subclasses incorrectly rejected as unsupported types.
• Segmentation fault on enum members whose value resolves back to the member.

Performance

• Up to 5x faster validation by working on Python objects directly instead of converting them to serde_json. #239
• Up to 2x faster meta.is_valid / meta.validate by working on Python objects directly instead of converting them to serde_json.