f: write trampoline hops as optional vec

Author: arik-so

lightning/src/events/mod.rs

@@ -1584,7 +1584,7 @@ impl Writeable for Event {
 					(9, None::<RouteParameters>, option), // retry in LDK versions prior to 0.0.115
 					(11, payment_id, option),
 					(13, failure, required),
-					(15, path.trampoline_hops, required_vec),
+					(15, path.trampoline_hops, optional_vec),
 				});
 			},
 			&Event::PendingHTLCsForwardable { time_forwardable: _ } => {