OpaMiddleware does not filter HTTP OPTIONS requests

# Run with: fastapi dev opa-poc.py --port 9999
from fastapi import FastAPI, Response, HTTPException
from fastapi_opa import OPAConfig, OPAMiddleware
from fastapi_opa.auth.auth_api_key import APIKeyAuthentication, APIKeyConfig

# OPA doesn't actually need to be running for this example
opa_host = "http://localhost:8181"
api_key_config = APIKeyConfig(
    header_key = 'ApiKey',
    api_key = 'secret-key',
)
api_key_auth = APIKeyAuthentication(api_key_config)
opa_config = OPAConfig(authentication=api_key_auth, opa_host=opa_host)

app = FastAPI()
app.add_middleware(OPAMiddleware, config=opa_config)

WRITABLE_ITEMS = {
    1: True,
    2: False,
}


@app.get("/")
async def root() -> dict:
    return {"msg": "success"}

@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id not in WRITABLE_ITEMS:
        raise HTTPException(status_code=404)
    return {"item_id": item_id}

@app.options("/items/{item_id}")
async def read_item_options(response: Response, item_id: int) -> dict:
    if item_id not in WRITABLE_ITEMS:
        raise HTTPException(status_code=404)

    response.headers["Allow"] = "OPTIONS, GET" + (", POST" if WRITABLE_ITEMS[item_id] else "")
    return {}

$ curl -i 'http://localhost:9999/items/1'
HTTP/1.1 401 Unauthorized
server: uvicorn
content-length: 26
content-type: application/json

{"message":"Unauthorized"}

$ curl -i 'http://localhost:9999/items/3'
HTTP/1.1 401 Unauthorized
server: uvicorn
content-length: 26
content-type: application/json

{"message":"Unauthorized"}

$ curl -i -X OPTIONS 'http://localhost:9999/items/1'
HTTP/1.1 200 OK
server: uvicorn
content-length: 2
content-type: application/json
allow: OPTIONS, GET, POST

{}

$ curl -i -X OPTIONS 'http://localhost:9999/items/2'
HTTP/1.1 200 OK
server: uvicorn
content-length: 2
content-type: application/json
allow: OPTIONS, GET

{}

$ curl -i -X OPTIONS 'http://localhost:9999/items/3'
HTTP/1.1 404 Not Found
server: uvicorn
content-length: 22
content-type: application/json

{"detail":"Not Found"}