Support swift syntax 602 (#5)

Author: heoblitz

Package.swift

@@ -18,7 +18,7 @@ let package = Package(
     ),
   ],
   dependencies: [
-    .package(url: "https://github.com/swiftlang/swift-syntax", "509.0.0"..<"602.0.0"),
+    .package(url: "https://github.com/swiftlang/swift-syntax", "509.0.0"..<"603.0.0"),
   ],
   targets: [
     .macro(