Implement opset 19

[Swopper050]

https://github.com/onnx/onnx/blob/main/docs/Changelog.md#version-19-of-the-default-onnx-operator-set

Operators to update:

• Cast
• CastLike
• Constant
• Equal
• Reshape
• Shape
• Identity

Also:

• Update max supported opset constant