feat: add maxspeed to transport layer

src/main/java/org/openmaptiles/layers/Transportation.java

@@ -497,6 +497,7 @@ public class Transportation implements
         .setAttr(Fields.CLASS, highwayClass)
         .setAttr(Fields.SUBCLASS, highwaySubclass(highwayClass, element.publicTransport(), highway))
         .setAttr(Fields.NETWORK, networkType != null ? networkType.name : null)
+        .setAttr("maxspeed", element.source().getTag("maxspeed"))
         .setAttrWithMinSize(Fields.BRUNNEL, brunnel(element.isBridge(), element.isTunnel(), element.isFord()), 4, 4, 12)
         // z8+
         .setAttrWithMinzoom(Fields.EXPRESSWAY, expressway ? 1 : null, 8)

src/test/java/org/openmaptiles/OpenMapTilesTest.java

@@ -201,7 +201,7 @@ class OpenMapTilesTest {
     ), 14, 828, LineString.class);
     assertNumFeatures("transportation", Map.of(
       "class", "primary"
-    ), 14, 249, LineString.class);
+    ), 14, 262, LineString.class);
   }
 
   @Test