Fix typo in example code

[kasperkarlsson]

Changes

Minor change to fix a typo in README.md

References

N/A

Testing

Please describe how this can be tested by reviewers. Be specific about anything not tested and reasons why. If this library has unit and/or integration testing, tests should be added for new functionality and existing tests should complete without errors.

• [ ] This change adds test coverage
• [ ] This change has been tested on the latest version of Java or why not

Checklist

• [X] I have read the Auth0 general contribution guidelines
• [X] I have read the Auth0 Code of Conduct
• [ ] All existing and new tests complete without errors