Fix 'An opening curly bracket must not be followed by a blank line.' issue in API.Boilerplate.Api\Startup.cs

[CodeFactor](https://www.codefactor.io/repository/github/devcomputaria/apiboilerplate) found an issue: An opening curly bracket must not be followed by a blank line.

It's currently on:
[API.Boilerplate.Api\Startup.cs:28](https://www.codefactor.io/repository/github/devcomputaria/apiboilerplate/source/main/API.Boilerplate.Api/Startup.cs#L28)