Fix typo in readme: Arrow function was not setup properly

[milan]

Description

Example in the readme had an error

Motivation and Context

Make it easier for other people to copy and paste the example code

How Has This Been Tested?

No test, it's just documentation

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.