Add 'global' region to Google provider options

[aelmiger]

Currently, the list of supported providers is missing the "global" option for the google vertex ai provider.

[DouweM]

@aelmiger global is already listed explicitly in the __init__ definitions:

pydantic-ai/pydantic_ai_slim/pydantic_ai/providers/google.py

Lines 72 to 83 in e7b2f82

	def __init__(
	self,
	*,
	api_key: str | None = None,
	credentials: Credentials | None = None,
	project: str | None = None,
	location: VertexAILocation | Literal['global'] | str | None = None,
	vertexai: bool | None = None,
	client: Client | None = None,
	http_client: httpx.AsyncClient | None = None,
	base_url: str | None = None,
	) -> None:

So I think this PR is unnecessary, but let me know if there's a scenario where you need it to be on VertexAILocation specifically. I'm not opposed to adding it there, but then we should remove it from the __init__ definitions.

[aelmiger]

Thanks for the fast response.
I missed the global in the __init__ definition. I was using VertexAILocation as a type hint and this resulted in an error.
It probably makes more sense to copy your format and type hint with VertexAILocation | Literal['global']