Update README.md
For "Add two peaks of Fe-55 source"(!115 (merged)): Three authors: Liejian Chen @chenlj, Maoqiang Jing @mjing and Xin Shi @xshi .
For "Add two peaks of Fe-55 source"(!115 (merged)): Three authors: Liejian Chen @chenlj, Maoqiang Jing @mjing and Xin Shi @xshi .