Update reclass-rs to ^0.6.0 (#1288)

Fixes projectsyn/reclass-rs#148 -- reclass-rs
didn't discover targets in subdirectories of `inventory/targets` without
compose-node-name (e.g. when compiling the kapitan-reference repo).

## Proposed Changes

* Update reclass-rs to `^0.6.0`

## Docs and Tests

* [ ] Tests added
* [ ] Updated documentation

Author: simu