docs: update contributors img (#17)

Author: thinkasany

README.md

@@ -489,9 +489,7 @@ To be developed...
 
 ## Contributors
 
-[<img src="https://avatars.githubusercontent.com/u/48346853" style="border-radius:50%;" width="30" height="30" alt="EternalHeart"/>](https://github.com/wh131462)
-[<img src="https://avatars.githubusercontent.com/u/61453917" style="border-radius:50%;" width="30" height="30" alt="SmartTeddy"/>](https://github.com/SmallTeddy)
-[<img src="https://avatars.githubusercontent.com/u/35305691" style="border-radius:50%;" width="30" height="30" alt="Hedwig-Fang"/>](https://github.com/Hedwig-Fang)
+<a href="https://github.com/EternalHeartTeam/leetcode-practice/graphs/contributors" target="_blank"><img src="https://raw.githubusercontent.com/EternalHeartTeam/leetcode-practice/svg/images/contributors.png" /></a>
 
 ## Feedback