releng: update versions to 0.8.0Change-Id: I6b067f3100a80028083ec70487b8c98cf1d5d868Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>Reviewed-on: https://git.eclipse.org/r/c/tracecompass.incubator/org.eclipse.tracecompass.incubator/+/205615Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>