Remove dependency on argument-parser

See swiftlang/swift-markdown#149

.gitignore

@@ -15,3 +15,4 @@ SymbolGraph.symbols.json
 .swiftpm
 Package.resolved
 .vscode
+/Tools/.build

Package.swift

@@ -1,6 +1,4 @@
-// swift-tools-version:5.2
-// In order to support users running on the latest Xcodes, please ensure that
-// [email protected] is kept in sync with this file.
+// swift-tools-version:5.5
 /*
  This source file is part of the Swift.org open source project
 

Tools/Package.swift

@@ -0,0 +1,31 @@
+// swift-tools-version:5.5
+/*
+ This source file is part of the Swift.org open source project
+ Copyright (c) 2023 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+ See https://swift.org/LICENSE.txt for license information
+ See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+*/
+
+import PackageDescription
+
+let package = Package(
+    name: "Tools",
+    products: [
+        .executable(name: "dump-unified-graph", targets: ["dump-unified-graph"]),
+    ],
+    dependencies: [
+        .package(name: "SymbolKit", path: "../."),
+        .package(url: "https://github.com/apple/swift-argument-parser", from: "1.2.2"),
+    ],
+    targets: [
+        .executableTarget(
+            name: "dump-unified-graph",
+            dependencies: [
+                .product(name: "SymbolKit", package: "SymbolKit"),
+                .product(name: "ArgumentParser", package: "swift-argument-parser")
+            ],
+            path: "dump-unified-graph"
+        ),
+    ]
+)