Fix Package.swift syntax error - remove trailing comma

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Co-Authored-By: Claude <noreply@anthropic.com>

Author: ldomaradzki

Package.swift

@@ -21,7 +21,7 @@ let package = Package(
             name: "xcsift",
             dependencies: [
                 .product(name: "ArgumentParser", package: "swift-argument-parser")
-            ],
+            ]
         ),
         .testTarget(
             name: "xcsiftTests",