Fixed mypy issue with /now endpoint

backend/moonstream/api.py

@@ -4,7 +4,7 @@ The Moonstream HTTP API
 import logging
 import time
 
-from fastapi import FastAPI, Form
+from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from . import data
@@ -41,7 +41,7 @@ async def version_handler() -> data.VersionResponse:
 
 
 @app.get("/now", tags=["time"])
-async def now_handler() -> int:
+async def now_handler() -> data.NowResponse:
     return data.NowResponse(epoch_time=time.time())