heroku - Couldn't find that process type (web) - (Procfile, gunicorn installed, heroku/python added, commit(empty-commit) & push tried)

Question

heroku - Couldn't find that process type (web) Done the instructions by developer6811 but still get error:

Scaling dynos... !
▸    Couldn't find that process type (web).

after doing

$ heroku ps:scale web=1

some instructions that shows my condition:

$ pip install gunicorn
Requirement already satisfied: gunicorn in c:\users\adolp\anaconda3\lib\site-packages (20.1.0)
Requirement already satisfied: setuptools>=3.0 in c:\users\adolp\anaconda3\lib\site-packages (from gunicorn) (52.0.0.post20210125)

$git commit --allow-empty -m "Adjust buildpacks on Heroku"
[main 92d6f48] Adjust buildpacks on Heroku

$git push heroku master
Everything up-to-date

$git push heroku main
Everything up-to-date

$heroku buildpacks:add heroku/python
 »   Error: The buildpack heroku/python is already set on your app.

app.py:

from flask import Flask
app = Flask(__name__)

@app.route("/")#decorator
def home():
    return "Hello Flask 2"
@app.route("/test")#decorator
def test():
    return "This is Test"
if __name__=="__main__":
    app.run() 

Procfile:

web: gunicorn app:app

Requirements.txt:

Flask
gunicorn

runtime.txt:

python-3.9.11

project folder image