releng: update versions to 0.2.0Updated for Trace Compass 8.0.0 releaseModified update_version.sh to update trace-server .product file.Added check_plugins_changes.sh to update the patch version in manifestfiles when the plug-in code has been modified.Change-Id: Id5831baad57471baa50293e45e4ada72df9cc9bbSigned-off-by: Patrick Tasse <patrick.tasse@gmail.com>Reviewed-on: https://git.eclipse.org/r/c/tracecompass.incubator/org.eclipse.tracecompass.incubator/+/193909Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>