rtt: 2.7.0-rc1-0 in 'hydro/release.yaml' [bloom]

Increasing version of package(s) in repository `rtt`:
- previous version: `2.6.9-2`
- new version: `2.7.0-rc1-0`
- distro file: `hydro/release.yaml`
- bloom version: `0.4.4`