docs: add contributor profile link to README

Author: Mukller

README.md

@@ -130,4 +130,8 @@ If you find `layoutparser` helpful to your work, please consider citing our tool
   journal={arXiv preprint arXiv:2103.15348},
   year={2021}
 }
-```
+```
+
+---
+
+*[Mukller](https://github.com/Mukller)*