feat: use transparent logo

Author: simpleapples

README.md

@@ -1,5 +1,5 @@
 <div align="center">
-<img width="256" src="https://github.com/simpleapples/chatgpt-translator/blob/master/icon/icons/png/512x512.png">
+<img width="256" src="https://github.com/simpleapples/chatgpt-translator/blob/master/assets/icons/512x512.png">
 <h1>ChatGPT Translator</h1>
 <h4><i>The logo is generated by Midjourney, this README is partly generated by ChatGPT</i></h4>
 </div>