npc.php: increase trade route variety by 50%

NPCs often end up using the same ports over and over again because those
ports are part of the same top-profit routes. By increasing the number
of routes the NPCs select from, we should see a bit more variety in
which ports are used.

src/tools/npc/npc.php

@@ -535,7 +535,7 @@ function findRoutes(AbstractPlayer $player): array {
 
 	$maxNumberOfPorts = 2;
 	$routesForPort = -1;
-	$numberOfRoutes = 100;
+	$numberOfRoutes = 150;
 	$maxDistance = 15;
 
 	$db = Database::getInstance();