Revert committing `parallelizeBuildables` to `NO`

Trio.xcodeproj/xcshareddata/xcschemes/Trio.xcscheme

@@ -3,7 +3,7 @@
    LastUpgradeVersion = "1620"
    version = "1.3">
    <BuildAction
-      parallelizeBuildables = "NO"
+      parallelizeBuildables = "YES"
       buildImplicitDependencies = "YES">
       <BuildActionEntries>
          <BuildActionEntry