Update README.md

Author: eunwoo1104

README.md

@@ -7,7 +7,7 @@ Normal usage:
 import discord
 from discord.ext import commands
 from discord_slash import SlashCommand
-from discord_slash.model import SlashContext
+from discord_slash import SlashContext
 
 bot = commands.Bot(command_prefix="!", intents=discord.Intents.all())
 slash = SlashCommand(bot)