Update level_3.json

change level background to night

Author: marblexu

source/data/map/level_3.json

@@ -1,5 +1,5 @@
 {
-    "background_type":0,
+    "background_type":1,
     "init_sun_value":50,
     "zombie_list":[
         {"time":20000, "map_y":0, "name":"Zombie"},
@@ -17,4 +17,4 @@
         {"time":96000, "map_y":1, "name":"BucketheadZombie"},
         {"time":97000, "map_y":1, "name":"FlagZombie"}
     ]
-}
+}