Update Supported Swift Versions

This patch was authored and released by @0xTim.

This removes support for Swift 5.2 and Swift 5.3, making Swift 5.4 the earliest supported version as
announced

Clarify "same route with different parameter names" error message

This patch was authored and released by @gwynne.

An attempt to improve the error message for this unusual case.

Also ensures the error appears in release builds.

Add `AnyRouter` type-eraser

This patch was authored by @maciesielka and released by @0xTim.

Adds AnyRouter type-eraser for storing arbitrary routing strategy over a type controlled by Vapor within its DefaultResponder

Treat `.anything` and `.parameter` as part of the same node in `TrieRouter`

This patch was authored by @maciesielka and released by @0xTim.

Treat named parameters (:name) and anything (*) components as the same node of the TrieRouter (#108)

Resolves #91

Add support for string interpolation to PathComponent

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

Enables call sites that use PathComponents to allow for string literals that make use of interpolation (#101).

In Vapor, this enables constants and other variables to be used in routes:

let api = app.grouped("version-\(Constants.apiVersion)")

Add access to components matched by catchall ('**')

This patch was authored and released by @stevapple.

Allows using Parameters.getCatchall() to get the components matched by catchall (**) (#94).

Fix String description of the router and add tests

This patch was authored and released by @stevapple.

Fixes TrieRouter.Node.description (#93):

• To match PathComponent's stringLiteral expression,
• To match the routing strategy of TrieRouter,

And adds tests for descriptions (#93).

Require catchall ('**') appears at end of path

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

Adds a precondition requiring that the catchall path component (**) only appear as the last component in a path (#95).

RoutingKit 4.0.0

Docs:
https://docs.vapor.codes/4.0/routing/

More information on Vapor 4 official release:
https://forums.swift.org/t/vapor-4-official-release-begins/34802

Release Candidate 1

Updates to Swift 5.2 and macOS 10.15. Adds additional CI + README updates.

Release candidates represent the final shift toward focusing on bug fixes and documentation. Breaking changes will only be accepted for critical issues. We expect a final release of this package shortly after Swift 5.2's release date.