Chapter 7.3.8.1 : Unnecessary async modifier

[9SMTM6]

The build function in that chapter has an async modifier, but doesnt use await. This also caused compilation issues for me, but that might just be me, removing the modifier solved them without issue.

[juanmaia]

Same for me, if you remove the async you need to also remove the await from the calls in main and test/api/helpers

so

let application = Application::build(configuration).await?; 
// should become
let application = Application::build(configuration)?;