How to ignore test directory with bash uploader

My app is built with Elixir, and I use the bash uploader at the end of my Github Actions config:

# .github/workflows/elixir.yml

name: Elixir CI

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

env:
  MIX_ENV: test
  CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
  MAILJET_API_KEY: ${{ secrets.MAILJET_API_KEY }}
  MAILJET_SECRET_KEY: ${{ secrets.MAILJET_SECRET_KEY }}

jobs:
  build:

    name: Build and test
    runs-on: ubuntu-latest

    strategy:
      matrix:
        elixir: [1.11.3]
        otp: [23.3]

    services:
      postgres:
        image: postgres:12
        ports: ['5432:5432']
        env:
          POSTGRES_PASSWORD: postgres
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

    steps:
    - uses: actions/checkout@v2

    - name: Set up Elixir
      uses: erlef/setup-elixir@885971a72ed1f9240973bd92ab57af8c1aa68f24
      with:
        elixir-version: ${{ matrix.elixir }} # Define the elixir version [required]
        otp-version: ${{ matrix.otp }} # Define the OTP version [required]

    - name: Restore dependencies cache
      uses: actions/cache@v2
      with:
        path: deps
        key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
        restore-keys: ${{ runner.os }}-mix-

    - name: Install dependencies
      run: mix deps.get

    - name: Compilation
      run: mix compile --warnings-as-errors

    - name: Run Credo
      run: mix credo --strict

    - name: Run tests
      run: mix coveralls.json
      env:
          DB_PASSWORD: postgres
          DB_HOST: postgres

    - name: Upload test coverage
      id: codecov
      run: bash <(curl -s https://codecov.io/bash)

I have never set up a codecov.yml file. But right now codecov is expecting test coverage for the test files as well - and I would like to ignore those. They are in a /test directory. Can I do this with a command in the elixir.yml file, or do I need to set up a codecov.yml file for this? If the latter, are there online instructions I can follow for my case?

You will need to set up a codecov.yml file to do this. You can view the documentation here