Amplify-cli@env renaming an environment

**Is your feature request related to a problem? Please describe.**
Is it possible to rename an environment from, say "maaster" to "master"? The issue I'm currently facing is that I did not rename the environment when I switched to amplify-cli@env (so my only environment is called: "NONE"). I would like to rename this NONE environment to `dev` while preserving existing backend resources.

**Describe the solution you'd like**
`amplify env rename dev`
`> Enter new name: (dev)`

**Describe alternatives you've considered**
Creating a new branch, although I have some data, currently, that I'd rather not lose.

**Additional context**
amplify-ci@env --version: 0.2.1-multienv.22