Until now `helmfile delete` with helm v3 had been failing when `--namespace` is provided. Helmfile was missing the fact that in helm v3 namespace must be passed instead of tiller-namespace to scope releases to be deleted.
```
err: release "b-1" failed: helm3rc2 exited with status 1:
Error: uninstall: Release not loaded: b-1: release: not found
in ./helmfile.yaml: release "b-1" failed: helm3rc2 exited with status 1:
Error: uninstall: Release not loaded: b-1: release: not found
```