Update Starlette (#5)

Author: ccaruceru

requirements.txt

@@ -2,7 +2,7 @@ slack-bolt==1.16.2
 google-cloud-storage==2.7.0
 uvicorn==0.20.0
 aiohttp==3.8.3
-starlette==0.24.0
+starlette==0.25.0
 python-json-logger==2.0.4
 
 # pin the sdk dependency of bolt