Vapor: 4.20.0 Release

This patch was authored by @ileitch and released by @tanner0101.

Adds a require(_:) helper to Parameters, allowing for more succinct parameter handling. (#2402)

Previously the optional case needed to be handled explicitly:

guard let name = req.parameters.get("name") else {
    throw Abort(.internalServerError)
}

Now it can be written as:

let name = try req.parameters.require("name")