Bump minimum Swift version to 6.1

Author: colemancda

Package.swift

@@ -1,6 +1,5 @@
-// swift-tools-version: 6.0
+// swift-tools-version: 6.1
 // The swift-tools-version declares the minimum version of Swift required to build this package.
-
 import CompilerPluginSupport
 import PackageDescription