Website Documentation Issue

[Brontomerus]

I've noticed a minor update needed for the Executor Documentation on your website. Since that documentation had been written, I've noticed that dask-cloudprovider must have changed their package structure when they added support for other cloud platforms. Its nothing huge, just want to help because its one of those small details that could get lost in the shuffle of daily work. Below is the change needed to reflect what folks will need as it sits today:

executor = DaskExecutor(
    cluster_class="dask_cloudprovider.FargateCluster",
    cluster_kwargs={
        "image": "prefecthq/prefect:latest",
        "n_workers": 5,
        ...
    },
)

And the change we'd need in there:

# there is now a '.aws' in the import path
from dask_cloudprovider.aws import FargateCluster

so this would now be:

from dask_cloudprovider.aws import FargateCluster
flow.executor = DaskExecutor(
    cluster_class="dask_cloudprovider.aws.FargateCluster",
    cluster_kwargs={
        "image": "prefecthq/prefect:latest",
        "n_workers": 5,
        ...
    }
)

[cicdw]

Hi @Brontomerus - would you like to open a PR with the suggested change? Here is the line where you would need to add the .aws. submodule: https://github.com/PrefectHQ/prefect/blob/master/src/prefect/executors/dask.py#L111