feat(create-context): don't use Shadow Root.

The Context's Consumer component does not need to have a ShadowRoot
because it would be very hard to style elements inside it. (part)

fixes matthewp#384

src/create-context.ts

@@ -76,7 +76,7 @@ function makeContext(component: ComponentCreator): Creator {
         const context = useContext(Context);
 
         return render(context);
-      }),
+      }, { useShadowDOM: false }),
 
       defaultValue,
     };