Setting minor version of elastic beanstalk node.js platform

Each Node.js platform version supports a few Node.js language versions. Valid Node.js versions, as well as the default version. Each Node.js version includes a respective version of npm (the Node.js package manager).

On Amazon Linux 2 platform versions, only the default Node.js version is pre-installed. You can use a package.json file in the root of your project source to specify the Node.js version you want your application to use. Refer to https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/nodejs-platform-packagejson.html

On Amazon Linux AMI platform versions (preceding Amazon Linux 2), all listed Node.js versions that a platform version supports are pre-installed on it. The default Node.js version applies when the NodeVersion option in the aws:elasticbeanstalk:container:nodejs namespace isn't set. Refer to https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/command-options-specific.html#command-options-nodejs

Further info and especially some gotchas are called out at https://docs.aws.amazon.com/elasticbeanstalk/latest/platforms/platforms-supported.html#platforms-supported.nodejs