fix: add Swift 6.1-6.3 workaround for trait propagation issue

Added explicit package dependencies for swift-rfc-7578 and swift-url-routing
as a workaround for SPM trait propagation bug in Swift 6.1-6.3.

Also added MemberImportVisibility upcoming feature flag to all targets.

Author: coenttb

Package.swift

@@ -48,3 +48,31 @@ let package = Package(
         )
     ]
 )
+
+#if swift(>=6.1) && swift(<6.3)
+// workaround for error:
+// error: exhausted attempts to resolve the dependencies graph, with the following dependencies unresolved:
+// * 'swift-rfc-7578' from https://github.com/swift-standards/swift-rfc-7578.git
+// * 'swift-url-routing' from https://github.com/pointfreeco/swift-url-routing
+package.dependencies.append(contentsOf: [
+    .package(url: "https://github.com/swift-standards/swift-rfc-7578", from: "0.1.0"),
+    .package(url: "https://github.com/pointfreeco/swift-url-routing", from: "0.1.0")
+])
+#endif
+
+
+
+for target in package.targets {
+    target.swiftSettings?.append(
+        contentsOf: [
+            .enableUpcomingFeature("MemberImportVisibility")
+        ]
+    )
+}
+
+//package.traits.insert(
+//    .default(
+//        enabledTraits: ["URLRouting"]
+//    )
+//)
+