Automatically open a PR to bump the calver (#4167)

* Update our tools package to Swift 6.1

Also improves the package layout with subdirectories 📁

* Update GenerateSDKMocks to be an Async command.

* Add a tool to bump the project CalVer every month.

* Add a workflow to automatically bump the calendar version.

Note: This only does year & month, the patch is handled by the release script.

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.7
+// swift-tools-version: 6.1
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
@@ -6,7 +6,7 @@ import PackageDescription
 let package = Package(
     name: "Element Swift",
     platforms: [
-        .macOS(.v13)
+        .macOS(.v14)
     ],
     products: [
         .executable(name: "tools", targets: ["Tools"])