Multiple passthrough variables for Docker & Docker Compose 🐳

Changed

• Docker#environment and DockerCompose#environment can now accept multiple string arguments to set a list of variables to pass through into a container all at once:

  docker {
      // Just one, previously supported
      environment 'FOO'
      environment 'BAR'
      // New - multiple arguments
      environment(
          'FOO',
          'BAR',
          'BAZ',
      )
      // Or more concisely
      environment 'FOO', 'BAR', 'BAZ'
  }