qt_gui_core: 0.2.20-0 in 'hydro/release.yaml' [bloom]

Increasing version of package(s) in repository `qt_gui_core`:
- previous version: `0.2.19-0`
- new version: `0.2.20-0`
- distro file: `hydro/release.yaml`
- bloom version: `0.4.4`