Laravel Spark on AWS CodePipeline / Beanstalk

Hello there, im trying to deploy my application through codepipeline to aws beanstalk. Since spark the deploy fails because I guess it needs the auth credentials in the composer config.

Currently I'm stuck how to add the credentials in CodePipeline.

I tried adding an composer.config file in the .ebextensions folder which loads the env variables from the beanstalk configuration.

container_commands:
  01-app-deploy:
    command: /bin/sh -c composer.phar config http-basic.spark.laravel.com ${SPARK_USERNAME} ${SPARK_API_TOKEN}

Poorly it still fails with the error message that it could not run composer install completely. In the log I can see that it can't pull the spark-stripe package.

Instance deployment failed to install Composer dependencies specified in 'composer.json' in your source bundle. The deployment failed. Instance deployment failed. For details, see 'eb-engine.log'.

So how can I add the credentials to the composer config in CodePipeline?