[Ruby] Release 0.43.0

Added

• validator_cls_for(schema) function to detect and return the appropriate validator class for a schema.

Fixed

• anyOf, format, unevaluatedProperties, and unevaluatedItems now correctly collect annotations per spec.

Performance

• Optimize pattern and patternProperties for ^(a|b|c)$ alternations via linear array scan.
• Optimize ^\S*$ patterns by replacing regex with a direct ECMA-262 whitespace check.