Fixed code sample for Optional use.

README.md

@@ -219,7 +219,7 @@ projectPager.lazyStream().limit(5).map(Project::getName).forEach(name -> System.
 ### **Java 8 Optional Support**
 GitLab4J-API supports Java 8 Optional<T> for API calls that result in the return of a single item. Here is an example on how to use the Java 8 Optional<T> API calls:
 ```java
-Optional<Group> optionalGroup =  gitlabApi.getGroupApi().getGroup("my-group-path");
+Optional<Group> optionalGroup =  gitlabApi.getGroupApi().getOptionalGroup("my-group-path");
 if (optionalGroup.isPresent())
     return optionalGroup.get();