Bump ipython version to fix security vulnerability

Author: Anirudh Goel

requirements.txt

@@ -25,7 +25,7 @@ Flask-User==1.0.1.5
 Flask-WTF==0.14.2
 gunicorn==19.9.0
 idna==2.8
-ipython==7.16.1
+ipython==7.16.3
 ipython-genutils==0.2.0
 isort==5.8.0
 itsdangerous==1.1.0