Update ziyin.md

Author: pliang279

src/content/people/ziyin.md

@@ -1,6 +1,6 @@
 ---
 name: "Ziyin Liu"
 title: "Visiting researcher"
-avatar: "https://www.mit.edu/~ziyinl/photo3.png"
+avatar: "./images/ziyin.png"
 website: "https://www.mit.edu/~ziyinl/"
 ---