update to use object with graphql() vs 3 params

Author: thall1961

src/content/graphql-js/Tutorial-GettingStarted.md

@@ -33,14 +33,18 @@ var schema = buildSchema(`
 `);
 
 // The root provides a resolver function for each API endpoint
-var root = {
+var rootValue = {
   hello: () => {
     return 'Hello world!';
   },
 };
 
 // Run the GraphQL query '{ hello }' and print out the response
-graphql(schema, '{ hello }', root).then((response) => {
+graphql({
+  schema,
+  source: '{ hello }',
+  rootValue
+}).then((response) => {
   console.log(response);
 });
 ```