robot_localization: 2.1.2-1 in 'indigo/distribution.yaml' [bloom]

Increasing version of package(s) in repository `robot_localization` to `2.1.2-1`:

- distro file: `indigo/distribution.yaml`
- bloom version: `0.5.8`
- previous version for package: `2.1.2-0`

## robot_localization

```
* Updated covariance correction formulation to "Joseph form" to improve filter stability.
* Implemented new versioning scheme.
```