Az-account-switcher

- Removed `az.cli` with `azure-cli` dependencies in favor of subprocess call.
- Assuming `az` in on your PATH.
- This makes the package with fast to install.
- Drop Python 3.7 support, due to minimal version supported by (dev) dependency `commitizen`.

- **Speed-up switching** by removing the online interaction pulling the Subscriptions through the Azure-CLI. [PR-7](https://github.com/abij/az-account-switcher/pull/7)
- Removed deprecated `get_azure_cli_credentials` in [PR-6](https://github.com/abij/az-account-switcher/pull/6)
- Add `--verbose` flag as an alias to the `-v` flag.

Main change is support for Windows

**Changes**

- Support Windows by changing interaction with Azure-CLI using Python package 'az.cli' instead of subprocess
- Drop Python 3.6 support, due to dependent package 'az.cli' using => 3.7
- Add unit tests running on latest versions of Unix, Windows and MacOs
- Depend on `azure-cli` instead of `azure-cli-core` to auto include `packaging` to fix [issue-3](https://github.com/abij/az-account-switcher/issues/3)

Some small improvements:

- Don't switch when same subscription is selected.
- Add `-v` verbose flag to print Azure-CLI sub-commands.
- Add `-h` as alias for `--help`

**Changes:**

- Include Python 3.6, not only greater then.
- Add DeepSource code checker and resolve found issue (related to shell=true)
- Add aliases for command-line next to az-switch: + az-account-switch + az-account-switcher _(the package name)_
- Dump to v1.0.0, since it's working fine for a while and looks better!

Add support for subscriptions in state disabled