feat: add fileSystemSynchronized properties to public helpers (#928)

* Add fileSystemSynchronized properties

* Addressed lint

Author: Econa77

Sources/XcodeProj/Objects/Project/PBXProj.swift

@@ -177,6 +177,14 @@ public extension PBXProj {
     var sourcesBuildPhases: [PBXSourcesBuildPhase] { Array(objects.sourcesBuildPhases.values) }
     var carbonResourcesBuildPhases: [PBXRezBuildPhase] { Array(objects.carbonResourcesBuildPhases.values) }
     var buildPhases: [PBXBuildPhase] { Array(objects.buildPhases.values) }
+    var fileSystemSynchronizedRootGroups: [PBXFileSystemSynchronizedRootGroup] { Array(objects.fileSystemSynchronizedRootGroups.values) }
+    var fileSystemSynchronizedBuildFileExceptionSets: [PBXFileSystemSynchronizedBuildFileExceptionSet] {
+        Array(objects.fileSystemSynchronizedBuildFileExceptionSets.values)
+    }
+
+    var fileSystemSynchronizedGroupBuildPhaseMembershipExceptionSet: [PBXFileSystemSynchronizedGroupBuildPhaseMembershipExceptionSet] {
+        Array(objects.fileSystemSynchronizedGroupBuildPhaseMembershipExceptionSet.values)
+    }
 
     /// Returns root project.
     func rootProject() throws -> PBXProject? {