fix bid typo

Author: snu-BuMinSeong

carrot/app/auction/services.py

@@ -48,9 +48,9 @@ async def place_bid(self, auction_id: str, bidder_id: str, bid_price: int) -> Bi
         auction.bid_count += 1
         await self.repository.update_auction_without_commit(auction)
 
-        await self.db_session.commit()
-        await self.db_session.refresh(new_bid)
-        await self.db_session.refresh(auction)
+        await self.session.commit()
+        await self.session.refresh(new_bid)
+        await self.session.refresh(auction)
         return new_bid
 
     async def get_top_bid(self, auction_id: str) -> Bid: