[434296] Reference the new contributor id

The diagram editor contributor id has been changed during the Diagram
split. Its is now org.eclipse.sirius.diagram.ui

Bug: 434296
Change-Id: Iec6f17793738bdb05a4aa6f0d795392cc49f1be4
Signed-off-by: Maxime PORHEL <maxime.porhel@obeo.fr>
[build] Refresh the Luna and canary target platforms

Change-Id: I1359c51b49786ba59e45ae0017d95c0ae0244795
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>