feat: update model ratio

relay/channel/openai/constant.go

@@ -9,6 +9,7 @@ var ModelList = []string{
 	"gpt-4-turbo-preview", "gpt-4-turbo", "gpt-4-turbo-2024-04-09",
 	"gpt-4-vision-preview",
 	"gpt-4o", "gpt-4o-2024-05-13",
+	"gpt-4o-mini", "gpt-4o-mini-2024-07-18",
 	"text-embedding-ada-002", "text-embedding-3-small", "text-embedding-3-large",
 	"text-curie-001", "text-babbage-001", "text-ada-001",
 	"text-moderation-latest", "text-moderation-stable",