Rename package to match repo

Motivation:

SE-0226 changes how SPM resolves a dependency graph and as part of the accepted proposal was to require package names to match their repo URL segments.

Modifications:

Change package from `redis-nio` to `swift-redis-nio-client`

Result:

The project should compliant with SE-0226: https://github.com/apple/swift-evolution/blob/master/proposals/0226-package-manager-target-based-dep-resolution.md

Package.swift

@@ -16,7 +16,7 @@
 import PackageDescription
 
 let package = Package(
-    name: "redis-nio",
+    name: "swift-redis-nio-client",
     products: [
         .library(name: "RedisNIO", targets: ["RedisNIO"])
     ],