How to skip Dockerfile when deploying to App Platform?

I have a repo with Flask app which I copied from https://github.com/digitalocean/sample-flask.

For development purposes only, I’ve created a minimal Dockerfile.

Now, when I try to deploy the app to App Platform it tries to deploy it as Docker app, however I want to deploy it as Python app.

I’ve added .do/app.yaml and .do/deploy.template.yaml but no luck.

Just in case, here are my configs:

# app.yaml
name: backend
services:
- environment_slug: python
  github:
    branch: main
    deploy_on_push: true
    repo: simetrique/backend
  name: backend
  run_command: gunicorn --worker-tmp-dir /dev/shm --config gunicorn_config.py main:app


# deploy.template.yaml
spec:
  name: backend
  services:
  - environment_slug: python
    git:
      branch: main
      repo: https://github.com/simetrique/backend.git
    name: backend
    run_command: gunicorn --worker-tmp-dir /dev/shm --config gunicorn_config.py main:app