GitHub Action for aws-cli

I'm opening this issue to gather feedback about the need for an AWS CLI GitHub Action in the github.com/aws-actions organization. Please use the thumbs-up reaction if this would be useful to you.

For context, GitHub deprecated (and has now deleted) their action `actions/aws/cli`. That action enabled running workflows like this:
```
- name: Upload to S3
uses: actions/aws/cli@master
with:
args: s3 cp ./results/ s3://reports/results/ --recursive
```

Please note that the AWS CLI is [pre-installed in the GitHub-hosted environments](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/software-installed-on-github-hosted-runners#ubuntu-1804-lts). For example, `runs-on: ubuntu-latest` will have AWS CLI version 1.16.299, and you can do the following:
```
- name: Upload to S3
run: |
aws s3 cp ./results/ s3://reports/results/ --recursive
```
I do not know how often GitHub will upgrade the version of the AWS CLI in the GitHub-hosted environments.

I have already received multiple requests for an AWS CLI action in the existing action repos that I maintain:
https://github.com/aws-actions/configure-aws-credentials/issues/9
https://github.com/aws-actions/amazon-ecs-deploy-task-definition/issues/21
https://github.com/aws-actions/amazon-ecs-deploy-task-definition/issues/18