add aggregate targets to project

Sources/XcodeGenKit/PBXProjGenerator.swift

@@ -214,7 +214,10 @@ public class PBXProjGenerator {
             .merged(generateTargetAttributes() ?? [:])
 
         pbxProject.object.knownRegions = sourceGenerator.knownRegions.sorted()
-        pbxProject.object.targets = targetObjects.values.sorted { $0.object.name < $1.object.name }.map { $0.reference }
+        let allTargets: [ObjectReference<PBXTarget>] = Array(targetObjects.values) + Array(targetAggregateObjects.values.map { ObjectReference(reference: $0.reference, object: $0.object) })
+            pbxProject.object.targets = allTargets
+                .sorted { $0.object.name < $1.object.name }
+                .map { $0.reference }
         pbxProject.object.attributes = projectAttributes
 
         return pbxProj

Tests/Fixtures/TestProject/Project.xcodeproj/project.pbxproj

@@ -926,6 +926,7 @@
 				NT_438704538506 /* Framework_watchOS */,
 				LT_479264660374 /* Legacy */,
 				NT_399755008402 /* StaticLibrary_ObjC */,
+				AT_445731917037 /* SuperTarget */,
 				NT_935153865209 /* iMessageApp */,
 				NT_618687462494 /* iMessageExtension */,
 			);