Add itsdangerous version to requirements.txt

[bentaljaard]

I am receiving the following error trying to build the image:

[pid 65:tid 139664763451584] File "/opt/app-root/lib64/python3.8/site-packages/flask/json/init.py", line 15, in
[Wed Mar 09 13:15:41.284667 2022] [wsgi:error] [pid 65:tid 139664763451584] from itsdangerous import json as _json
[Wed Mar 09 13:15:41.284677 2022] [wsgi:error] [pid 65:tid 139664763451584] ImportError: cannot import name 'json' from 'itsdangerous' (/opt/app-root/lib64/python3.8/site-packages/itsdangerous/init.py)

Adding itsdangerous==2.0.1 to requirements.txt resolves the problem.