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/Commands/DownloadStrings.swift

@@ -0,0 +1,24 @@
+import ArgumentParser
+import CommandLineTools
+import Foundation
+
+struct DownloadStrings: ParsableCommand {
+    static let configuration = CommandConfiguration(abstract: "A tool to download localizable strings from localazy")
+
+    @Flag(help: "Use to download translation keys for all languages")
+    var allLanguages = false
+
+    func run() throws {
+        try localazyDownload()
+        try swiftgen()
+    }
+
+    private func localazyDownload() throws {
+        let arguments = allLanguages ? " all" : ""
+        try Zsh.run(command: "localazy download\(arguments)")
+    }
+
+    private func swiftgen() throws {
+        try Zsh.run(command: "swiftgen config run --config Tools/SwiftGen/swiftgen-config.yml")
+    }
+}