[Ruby] Release 0.49.0

Added

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

Changed

• Invalid UTF-8, unsupported types, and nesting past the depth limit are reported only where a keyword reads the value.
• A hash keyed by both :name and "name" counts two properties (it previously collapsed them into one).

Fixed

• multipleOf incorrectly accepted integers past u64 that are not multiples of the divisor.

Performance

• Up to 3x faster validation by working on Ruby objects directly instead of converting them to serde_json. #239