Install the requirements file with pip install -r requirements.txt.
You will need to create a GitHub app if you have not already done so. On your user, go to Settings > Developer Settings > GitHub App > New GitHub App
Give your app a name, URL, disable the webhook. Once you create the app, you will need to note the application_id for later.
Once your app has been created, navigate to the general settings page and scroll down to find the Private Keys section. Generate a private key and copy it to the folder where this script lives.
Finally, you need to install the application somewhere. I would recommend installing it to your local user's GitHub account for testing purposes. Once installed, you should be able to find a numeric identifier in the URL bar, this is the installation_id.
Once you have all those pieces, you can run the script to generate a temporary token:
python3 generate_github_token.py <application_id> <installation_id> <path_to_private_key_pem_file>