Desktop: invalidate dive cache on equipment edit

Owing to the recent undo-changes, the git id was not invalidated
when accepting changes to cylinders and weights.

Do this in the MODIFY_DIVES macro for now.

Reported-by: Jan Iversen <jani@apache.org>
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

desktop-widgets/tab-widgets/TabDiveEquipment.cpp

@@ -152,6 +152,7 @@ void TabDiveEquipment::editWeightWidget(const QModelIndex &index)
 #define MODIFY_DIVES(DIVES, WHAT)                            \
 	do {                                                 \
 		for (dive *mydive: DIVES) {                  \
+			invalidate_dive_cache(mydive);       \
 			WHAT;                                \
 		}					     \
 		mark_divelist_changed(true);                 \