iOS - update to 1.5.0-sync-rc6

Author: vaind

sync_flutter_libs/ios/objectbox_sync_flutter_libs.podspec

@@ -15,7 +15,7 @@ Pod::Spec.new do |s|
   s.source_files = 'Classes/**/*'
 
   s.dependency 'Flutter'
-  s.dependency 'ObjectBox', '1.5.0-sync-rc5'
+  s.dependency 'ObjectBox', '1.5.0-sync-rc6'
 
   # Flutter.framework does not contain a i386 or arm46. Only x86_64 simulators are supported.
   s.pod_target_xcconfig = { 'DEFINES_MODULE' => 'YES', 'VALID_ARCHS[sdk=iphonesimulator*]' => 'x86_64' }