feat: add GPT-4o support (#2082)

Reference:
- https://platform.openai.com/docs/models/gpt-4o
- https://openai.com/index/hello-gpt-4o/

service/src/chatgpt/index.ts

@@ -53,8 +53,8 @@ let api: ChatGPTAPI | ChatGPTUnofficialProxyAPI
         options.maxModelTokens = 32768
         options.maxResponseTokens = 8192
       }
-      // if use GPT-4 Turbo
-      else if (/-preview|-turbo/.test(model.toLowerCase())) {
+      // if use GPT-4 Turbo or GPT-4o
+      else if (/-preview|-turbo|-o/.test(model.toLowerCase())) {
         options.maxModelTokens = 128000
         options.maxResponseTokens = 4096
       }