How to copy a generated file from a GitHub Actions workflow to a Cloud Function?

I'm using a GitHub Actions to deploy to a Google Cloud Function. The steps in my workflow include:

steps:
    - name: "Checkout repository"
      uses: actions/checkout@v3

    # Setup Python so we can install Pipenv and generate requirements.txt.
    - name: "Setup Python"
      uses: actions/setup-python@v4
      with:
        python-version: '3.10' 

    - name: "Install Pipenv"
      run: |
          pipenv requirements > requirements.txt
          ls -la
          cat requirements.txt

    - name: "Generate requirements.txt"
      run: pipenv requirements > requirements.txt

    - id: "auth"
      name: "Authenticate to Google Cloud"
      uses: "google-github-actions/auth@v0"
      with:
        workload_identity_provider: "..."
        service_account: "..."

    - id: "deploy"
      uses: "google-github-actions/deploy-cloud-functions@v0"
      with:
        name: "my-function"
        runtime: "python310"

Once I've generated the requirements.txt file I want that to be deployed along with my application code (checked out in the step above). The requirements.txt file gets generated during the build but it never gets deployed. (Confirmed by looking at the source in Cloud Functions).

How can I ensure this file is deployed along with my application code?

Update 1:

Here is the output after listing the contents of the directory after generating requirements.txt:

total 56
drwxr-xr-x 6 runner docker 4096 Sep  6 20:38 .
drwxr-xr-x 3 runner docker 4096 Sep  6 20:38 ..
-rw-r--r-- 1 runner docker  977 Sep  6 20:38 .env.example
-rw-r--r-- 1 runner docker  749 Sep  6 20:38 .gcloudignore
drwxr-xr-x 8 runner docker 4096 Sep  6 20:38 .git
drwxr-xr-x 3 runner docker 4096 Sep  6 20:38 .github
-rw-r--r-- 1 runner docker  120 Sep  6 20:38 .gitignore
-rw-r--r-- 1 runner docker  139 Sep  6 20:38 Pipfile
-rw-r--r-- 1 runner docker  454 Sep  6 20:38 Pipfile.lock
-rw-r--r-- 1 runner docker 1276 Sep  6 20:38 README.md
drwxr-xr-x 5 runner docker 4096 Sep  6 20:38 app
drwxr-xr-x 2 runner docker 4096 Sep  6 20:38 data
-rw-r--r-- 1 runner docker 2169 Sep  6 20:38 main.py
-rw-r--r-- 1 runner docker   27 Sep  6 20:38 requirements.txt

Update 2: Showing the contents of requirements.txt reveals it to only contain:

-i https://pypi.org/simple

No dependencies are included. This could well be the problem but I'm not yet sure why.

Update 3: The error shown in the deploy stage of the workflow is:

ModuleNotFoundError: No module named 'aiohttp'

This is because there is no requirements.txt file to install prior to running the function. aiohttp just happens to be the first dependency listed in my source code.