Fix Documentation: Event Handler REST API CORS example

[joel-aws]

In the example for CORS, line 3 should read:

from aws_lambda_powertools.event_handler.api_gateway import APIGatewayRestResolver, CORSConfig

Or CORSConfig should be added to __init__.py.

[boring-cyborg]

Thanks for opening your first issue here! We'll come back to you as soon as we can.

[michaelbrewer]

@joel-aws - sorry my bad, i fixed the docs and also added CORSConfig to __init__.py for ease of use in the future releases.

[joel-aws]

Thank you for your awesome work, @michaelbrewer; I just shared some of your latest changes on 1.25 with a colleague and we were stoked to use it!