Infra: remove unneeded swiftLanguageVersions param (#444) [skip ci]

Co-authored-by: Jeongsang Kim <[email protected]>
Co-authored-by: David Roman <[email protected]>

Author: 3 people

[email protected]

@@ -19,6 +19,5 @@ let package = Package(
             name: "SwiftUIIntrospect",
             path: "Sources"
         ),
-    ],
-    swiftLanguageVersions: [.v6]
+    ]
 )