Jinja no longer supports Escape

[rennsport]

As of version 3.1.0 of Jinja released March 24, 2022, Markup and Escape have been removed. The devs suggest importing them from MarkupSafe instead. See: https://jinja.palletsprojects.com/en/3.1.x/changes/#version-3-1-0

Flask 1.1.2 tries to import Escape from Jinja:

Traceback (most recent call last):
  File /usr/local/bin/nxbt, line 8, in <module>
    sys.exit(main())
  File /usr/local/lib/python3.8/dist-packages/nxbt/cli.py, line 321, in main
    from .web import start_web_app
  File /usr/local/lib/python3.8/dist-packages/nxbt/web/__init__.py, line 1, in <module>
    from .app import start_web_app
  File /usr/local/lib/python3.8/dist-packages/nxbt/web/app.py, line 9, in <module>
    from flask import Flask, render_template, request
  File /usr/local/lib/python3.8/dist-packages/flask/__init__.py, line 14, in <module>
    from jinja2 import escape
ImportError: cannot import name 'escape' from 'jinja2' (/usr/local/lib/python3.8/dist-packages/jinja2/__init__.py)

If you install Jinja2==3.0.3 you no longer have that specific error but then run into ImportError: cannot import name ‘json’ from itsdangerous which is also a Flask related issue requiring you to downgrade itsdangerous from 2.1.2 (at time of writing) to 2.0.1 and downgrade werkzeug from 2.1.1 to 2.0.2 before the webserver runs without issue.

[l4desu-mizu]

related to #61. (updating the dependencies to more recent flask versions works)