New flask release deprecates flask.json.JSONEncoder which is used by the pinned flask_wtf 0.x

[oegedijk]

So Flask 2.3.0 deprecates a bunch of json support: https://flask.palletsprojects.com/en/2.3.x/changes/#version-2-3-0

This has been anticipated in flask-wtf release 1.1.1.

However flask-simplelogin pins flask-wtf to 0.x:

Flask-WTF = "^0.15.1"

resulting in the following error in my explainerdashboard library that uses flask_simplelogin as a dependency:

ImportError while loading conftest '/home/runner/work/explainerdashboard/explainerdashboard/tests/conftest.py'.
tests/conftest.py:21: in <module>
    from explainerdashboard import RegressionExplainer, ClassifierExplainer, ExplainerDashboard, ExplainerHub
explainerdashboard/__init__.py:5: in <module>
    from .dashboards import ExplainerDashboard, ExplainerHub, InlineExplainer
explainerdashboard/dashboards.py:41: in <module>
    from flask_simplelogin import SimpleLogin, login_required
/opt/hostedtoolcache/Python/3.9.[16](https://github.com/oegedijk/explainerdashboard/actions/runs/4856284560/jobs/8655687817#step:6:17)/x64/lib/python3.9/site-packages/flask_simplelogin/__init__.py:24: in <module>
    from flask_wtf import FlaskForm
/opt/hostedtoolcache/Python/3.9.16/x64/lib/python3.9/site-packages/flask_wtf/__init__.py:3: in <module>
    from .recaptcha import *
/opt/hostedtoolcache/Python/3.9.16/x64/lib/python3.9/site-packages/flask_wtf/recaptcha/__init__.py:2: in <module>
    from .fields import *
/opt/hostedtoolcache/Python/3.9.16/x64/lib/python3.9/site-packages/flask_wtf/recaptcha/fields.py:3: in <module>
    from . import widgets
/opt/hostedtoolcache/Python/3.9.16/x64/lib/python3.9/site-packages/flask_wtf/recaptcha/widgets.py:4: in <module>
    JSONEncoder = json.JSONEncoder
E   AttributeError: module 'flask.json' has no attribute 'JSONEncoder'

So would be great if you could upgrade the dependency of flask-wtf!