title: Firebase functions deployment: undefined environment datas with Github actions
body: <p>I'm trying to set up the GITHUB actions to deploy my firebase functions.
  The code of the action is:</p>
  <pre><code>name: Development Deploy Workflow
  'on':
    push:
      branches:
        - develop
  jobs:
    backend-deployment:
      name: Backend Development Deployment
      runs-on: ubuntu-latest
      steps:
        - name: Checkout GitHub repository
          uses: actions/checkout@v2
        - name: Install dependencies
          run: npm install 
        - name: Deploy to Firebase Functions
          uses: w9jds/firebase-action@master
          with:
            args: deploy -P development --only functions           
          env:
            GCP_SA_KEY: '${{ secrets.GCP_SA_KEY }}'
  </code></pre>
  <p>When the action runs I get this error:</p>
  <pre><code>✔  functions: Finished running predeploy script.
  i  functions: ensuring required API cloudfunctions.googleapis.com is enabled...
  i  functions: ensuring required API cloudbuild.googleapis.com is enabled...
  ✔  functions: required API cloudbuild.googleapis.com is enabled
  ✔  functions: required API cloudfunctions.googleapis.com is enabled
  
  Error: Error occurred while parsing your function triggers.
  
  TypeError: Cannot read property 'private_key' of undefined
      at Object.&lt;anonymous&gt; (/github/workspace/lib/services/Firebase.service.js:29:47)
  
  </code></pre>
  <p>The line with the code is:</p>
  <pre><code>const { private_key } = functions.config().service_account
  
  </code></pre>
  <p>I don't understand why <strong>functions.config() is empty</strong> because I can deploy my functions from my local machine without any problem and in three different environments.
  can anyone help me?
  Thanks in advance.</p>