Support for more Schema types like anyOf

[icnahom]

Description of the feature request:

The current Schema types is missing important type like anyOf.

Here are the schema types: https://cloud.google.com/vertex-ai/generative-ai/docs/multimodal/control-generated-output#fields

What problem are you trying to solve with this feature?

Once all schema types supported by Gemini 1.5 Pro are added to this package I will be able to utilize them as I need.

Any other information you'd like to share?

With no support for anyOf, the current json output is not as structured as expected. But when I provide a schema with anyOf in the prompt , I get the output I needed with no missed or misplaced json fields.