driver_common: 1.6.8-0 in 'hydro/distribution.yaml' [bloom]

Increasing version of package(s) in repository `driver_common` to `1.6.8-0`:

- distro file: `hydro/distribution.yaml`
- bloom version: `0.5.10`
- previous version for package: `1.6.7-0`

## driver_base

- No changes

## driver_common

- No changes

## timestamp_tools

- No changes