Add photo for Mike Istomin

Author: christymelucci

content/people/index.md

@@ -299,7 +299,7 @@ people:
   note: Core member, March-May 2020; Contributor, June 2020-May 2021
 - firstName: Mike
   lastName: Istomin
-  image: profile-placeholder.png
+  image: mike-istomin.jpg
   affiliation: CMU & StartupSoft
   team:
   - core