Generate the openapi_schema for a specific api version using the app.openapi() method

[ddoren]

Is your feature request related to a problem? Please describe.
Hey, I'm trying to generate the full openapi.json file for a specific API version without running the server, programmatically, as I need to generate the html documentation from it. Is there a way to do that? using the app.openapi() would hide the endpoints behind the versions.
But I need the openapi schema for a specific API version.

Describe the solution you'd like
A method that would allow the generation of a specific versioned openapi schema, something like app.openapi('v1') or anything would work really.

Additional context

from fastapi.openapi.utils import get_openapi
from app import app
import json


with open("openapi.json", "w") as file:
    json.dump(app.openapi(), file)


with open("openapi-get.json", "w") as file:
    openapi_schema = get_openapi(
        title="Custom title",
        version="2.5.0",
        description="This is a very custom OpenAPI schema",
        routes=app.routes,
    )

The generated openapi schema includes the v0 and v1 endpoints, however need a method to generate the schema with the endpoints for a specific version.