title: missing .env file in gitlab CI
body: <p>So I have a react native app in my repo that I'm working on and in my repo I have a .env file that I'm ignoring so that my secrets don't get exposed and a .env-example file of important environment variables to configure. My problem is, since I'm not pushing the .env file to my repo, when I deploy my app through the google app engine(this is done in the deployment stage in my gitlab-ci.yml file), these environment variables will not be present in production and I need them for my app to work as I do something like this in my build.gradle file.</p>
  
  <pre><code>   defaultConfig {
      applicationId "com.beecash.app"
      minSdkVersion rootProject.ext.minSdkVersion
      multiDexEnabled true // enabled for adding play service dependency
      targetSdkVersion rootProject.ext.targetSdkVersion
      versionCode 19
      versionName "0.10.1"
      manifestPlaceholders = [
          BRANCH_LIVE_KEY: project.env.get('BRANCH_LIVE_KEY'),
          BRANCH_TEST_KEY: project.env.get('BRANCH_TEST_KEY'),
          BRANCH_TEST_MODE: project.env.get('BRANCH_TEST_MODE'),
          CLEVERTAP_ACCOUNT_ID: project.env.get('CLEVERTAP_ACCOUNT_ID'),
          CLEVERTAP_TOKEN: project.env.get('CLEVERTAP_TOKEN')
      ]
  }
  </code></pre>