No ability to specify SSH public keys for CodeCommit

### Name of the resource

AWS::IAM::User

### Resource name

_No response_

### Description

CodeCommit requires IAM users with SSH public keys specified. Unfortunately, no CloudFormation resource currently exists that would map to the following API method:

https://docs.aws.amazon.com/IAM/latest/APIReference/API_UpdateSSHPublicKey.html

In other words, there's no way to specify the SSH public key of an IAM user through CloudFormation.

### Other Details

_No response_

Review the AWS::IAM::User resource coverage and the linked IAM UpdateSSHPublicKey API method first. Define the resource property and lifecycle scope needed to declare an IAM user's SSH public key through CloudFormation. Done means the requested public key can be specified for CodeCommit users through a CloudFormation resource.

Written by the indexing model from the issue text.