Upgrade Flask version to 2.0.3

[pingyangtiaer]

If I clone the current code and run docker-compose up python after I ran docker-compose build python, I got errors:

Attaching to python
python  | Traceback (most recent call last):
python  |   File "/usr/local/lib/python3.7/runpy.py", line 193, in _run_module_as_main
python  |     "__main__", mod_spec)
python  |   File "/usr/local/lib/python3.7/runpy.py", line 85, in _run_code
python  |     exec(code, run_globals)
python  |   File "/usr/local/lib/python3.7/site-packages/ptvsd/__main__.py", line 446, in <module>
python  |     main(sys.argv)
python  |   File "/usr/local/lib/python3.7/site-packages/ptvsd/__main__.py", line 432, in main
python  |     run()
python  |   File "/usr/local/lib/python3.7/site-packages/ptvsd/__main__.py", line 342, in run_module
python  |     run_module_as_main(target, alter_argv=True)
python  |   File "/usr/local/lib/python3.7/runpy.py", line 183, in _run_module_as_main
python  |     mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
python  |   File "/usr/local/lib/python3.7/runpy.py", line 142, in _get_module_details
python  |     return _get_module_details(pkg_main_name, error)
python  |   File "/usr/local/lib/python3.7/runpy.py", line 109, in _get_module_details
python  |     __import__(pkg_name)
python  |   File "/usr/local/lib/python3.7/site-packages/flask/__init__.py", line 19, in <module>
python  |     from jinja2 import Markup, escape
python  | ImportError: cannot import name 'Markup' from 'jinja2' (/usr/local/lib/python3.7/site-packages/jinja2/__init__.py)

I searched through google, if I replace the line in the requirements.txt with Flask == 2.0.3 Everything works.

[marceldempers]

fixed! thanks for that