Tracking issue for AWS CLI v2

Problem

Version 1.0.0 of the AWS CLI was tagged just over 5 years ago. In that time, a lot has changed. We've received tons of feedback from customers. We've learned what features customers enjoy, and what parts of the CLI we'd like to change. There are changes we've wanted to make, but needed to wait until the next major version of the AWS CLI due to either the backwards incompatible nature or the large scope of the change. Well, we're here now. This issue is to track all the work for CLI v2. We wanted to do this work on GitHub right from the beginning. Even though we're in the early stages of development, community feedback will play an important role in its development. Any AWS CLI v2 related issue/PR will be labeled with v2. We'll also reference this issue for any AWS CLI v2 related PRs so everyone can see all the changes we're making. * All the development work will be in the v2 branch. If you have an idea for CLI v2, whether it's a new feature or a change we couldn't make in v1 of the AWS CLI, please feel free to open a GitHub issue and let us know. You can also go through any issue labeled as CLI v2 and +1 features that you'd like to see us implement. Blog: https://aws.amazon.com/blogs/developer/aws-cli-v2-development/