catkin: 0.5.81-0 in 'groovy/distribution.yaml' [bloom]

Increasing version of package(s) in repository `catkin` to `0.5.81-0`:

- distro file: `groovy/distribution.yaml`
- bloom version: `0.5.1`
- previous version for package: `0.5.77-0`

## catkin

```
* fix generated find_package() logic when used from dry packages: remove debug_message usage from generated pkgConfig.cmake files (#583 <https://github.com/ros/catkin/issues/583>)
* fix EXPORTED_TARGETS argument for catkin_package() (#581 <https://github.com/ros/catkin/issues/581>)
```