rail_maps: 0.2.1-0 in 'hydro/distribution.yaml' [bloom]

Increasing version of package(s) in repository `rail_maps` to `0.2.1-0`:

- distro file: `hydro/distribution.yaml`
- bloom version: `0.5.2`
- previous version for package: `null`

## rail_maps

```
* readme fix
* cleanup for release
* command_center added
* Contributors: Russell Toris
```