Change sheme to run tests on Release build

Author: Mariana Lenetis and Tim Kersey

JSONHelper.xcodeproj/xcshareddata/xcschemes/JSONHelper-iOS.xcscheme

@@ -40,7 +40,7 @@
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
-      buildConfiguration = "Debug">
+      buildConfiguration = "Release">
       <Testables>
          <TestableReference
             skipped = "NO">