Modified Flask version in requirement.txt for solving dependency conflict

[KarthiDreamr]

Purpose

This PR is intended to resolve dependency issues in the requirements.txt file caused by an old version of Flask. By changing the Flask version to 3.0.0, the PR aims to fix the import error related to url_quote from werkzeug.urls.
In addition to the Flask version change, the PR also requests to change the instruction for creating a virtual environment from py -m venv .venv to python -m venv .venv to avoid issues in the process.

Does this introduce a breaking change?

[x] Yes
[ ] No

Pull Request Type

What kind of change does this Pull Request introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:

How to Test

Follow the documentation as is after installing the latest python click here

What to Check

Verify that the following are valid without import errors unlike the existing code

• The application runs as expected with Flask version 3.0.0.

Other Information

The error I received after I ran flask run:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "C:\Users\karth\Documents\BoshWebAppDeploy\msdocs-python-flask-webapp-quickstart\.venv\scripts\flask.exe\__main__.py", line 4, in <module>
  File "C:\Users\karth\Documents\BoshWebAppDeploy\msdocs-python-flask-webapp-quickstart\.venv\Lib\site-packages\flask\__init__.py", line 7, in <module>
    from .app import Flask as Flask
  File "C:\Users\karth\Documents\BoshWebAppDeploy\msdocs-python-flask-webapp-quickstart\.venv\Lib\site-packages\flask\app.py", line 28, in <module>
    from . import cli
  File "C:\Users\karth\Documents\BoshWebAppDeploy\msdocs-python-flask-webapp-quickstart\.venv\Lib\site-packages\flask\cli.py", line 18, in <module>
    from .helpers import get_debug_flag
  File "C:\Users\karth\Documents\BoshWebAppDeploy\msdocs-python-flask-webapp-quickstart\.venv\Lib\site-packages\flask\helpers.py", line 16, in <module>
    from werkzeug.urls import url_quote
ImportError: cannot import name 'url_quote' from 'werkzeug.urls' (C:\Users\karth\Documents\BoshWebAppDeploy\msdocs-python-flask-webapp-quickstart\.venv\Lib\site-packages\werkzeug\urls.py)```