AWS CDK: Rename dimensions metric property to dimensionsMap

[Fahmeedha]

Describe the issue

One of the metric property is not updated in the documentation https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_cloudwatch.Metric.html#dimensions. The “dimension” metric property is supposed to be “dimensionsMap”.

Links

https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_cloudwatch.Metric.html#dimensions

[ahzia]

@madeline-k Can you check my draft PR,
I am a new contributor and this is my first PR, I appreciate any feedback, let me know If What I did is wrong and what is the right way to fix this.

[peterwoodworth]

I've given a review @ahzia 🙂