docs: update readme

Author: simpleapples

README.md

@@ -1,4 +1,8 @@
-# GPT Translator
+<div align="center">
+<img width="256" src="https://github.com/simpleapples/gpt-translator/blob/master/icon/icons/png/512x512.png">
+<h1>GPT Translator</h1>
+<h4><i>The logo is generated by Midjourney, this README is partly generated by ChatGPT</i></h4>
+</div>
 
 GPT-Translator is an open-source project that allows you to translate text using GPT language model.