Fix XMLHttpRequest example

Author: slax57

README.md

@@ -455,7 +455,7 @@ Useful when using XMLHttpRequest directly or libraries such as [axios](https://w
 Add a `script` tag referencing the library:
 
 ```html
-<script src="../lib/json-graphql-server.min.js"></script>
+<script src="../lib/json-graphql-server.client.min.js"></script>
 ```
 
 It will expose the `JsonGraphqlServer` as a global object: