[serving] Update dependencies

setup.py

@@ -63,7 +63,7 @@ extras["sklearn"] = ["scikit-learn"]
 extras["tf"] = ["tensorflow"]
 extras["torch"] = ["torch"]
 
-extras["serving"] = ["pydantic", "uvicorn", "fastapi"]
+extras["serving"] = ["pydantic", "uvicorn", "fastapi", "starlette"]
 extras["all"] = extras["serving"] + ["tensorflow", "torch"]
 
 extras["testing"] = ["pytest", "pytest-xdist"]

src/transformers/commands/serving.py

@@ -2,7 +2,6 @@ import logging
 from argparse import ArgumentParser, Namespace
 from typing import Any, List, Optional
 
-from starlette.responses import JSONResponse
 from transformers import Pipeline
 from transformers.commands import BaseTransformersCLICommand
 from transformers.pipelines import SUPPORTED_TASKS, pipeline
@@ -13,6 +12,7 @@ try:
     from fastapi import FastAPI, HTTPException, Body
     from fastapi.routing import APIRoute
     from pydantic import BaseModel
+    from starlette.responses import JSONResponse
 
     _serve_dependancies_installed = True
 except (ImportError, AttributeError):