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.

Tools/Sources/Tools.swift

@@ -3,7 +3,7 @@ import Foundation
 
 @main
 struct Tools: AsyncParsableCommand {
-    static var configuration = CommandConfiguration(abstract: "A collection of command line tools for ElementX",
+    static let configuration = CommandConfiguration(abstract: "A collection of command line tools for ElementX",
                                                     subcommands: [BuildSDK.self,
                                                                   SetupProject.self,
                                                                   OutdatedPackages.self,
@@ -12,5 +12,6 @@ struct Tools: AsyncParsableCommand {
                                                                   GenerateSDKMocks.self,
                                                                   GenerateSAS.self,
                                                                   AppIconBanner.self,
-                                                                  UnusedStrings.self])
+                                                                  UnusedStrings.self,
+                                                                  BumpCalendarVersion.self])
 }