kapp app-group deploy does not work without app group name

It is clear the CLI is expecting a group-name flag. Wouldn't it be possible to take that from the name of the specified directory?
```
$ tree
.
└── something
├── svc.yaml
└── traefik.yaml
```
```
$ kapp app-group deploy --directory .
--- deploying app '-something' (namespace: default) from something

Error: Creating app: ConfigMap "-something" is invalid: metadata.name: Invalid value: "-something": a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')
```