Rename Package to "RediStack"

Motivation:

SwiftPM as of Swift 5.2 introduces a new package dependency graph and package description that makes the current naming of RediStack awkward to pull in.

Modifications:

- Change: Package.name to be "RediStack"

The git repo will be renamed to "mordil/redistack" in addition to this change.

Result:

Fixes #72 and makes it seamless to pull in RediStack as a Swift package dependency.

Package.swift

@@ -16,7 +16,7 @@
 import PackageDescription
 
 let package = Package(
-    name: "redi-stack",
+    name: "RediStack",
     products: [
         .library(name: "RediStack", targets: ["RediStack"]),
         .library(name: "RediStackTestUtils", targets: ["RediStackTestUtils"])