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

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

- distro file: `hydro/distribution.yaml`
- bloom version: `0.5.4`
- previous version for package: `0.2.0-0`

## segbot_gazebo

- No changes

## segbot_simulation_apps

- No changes

## segbot_simulator

```
* segbot_simulator: add segbot_simulation_apps dependency (#20 <https://github.com/utexas-bwi/segbot_simulator/issues/20>)
```