hu: update licenses of feeds maintained by me

I've made them more permissive to allow usage in Träwelling.

Author: gy-mate

feeds/hu.json

@@ -48,15 +48,15 @@
             "type": "http",
             "url": "https://gy-mate.hu/gtfs/gtfs_hu_funicular.zip",
             "license": {
-                "spdx-identifier": "GPL-3.0-only"
+                "spdx-identifier": "CC-BY-4.0"
             }
         },
         {
             "name": "bkk-chairlift",
             "type": "http",
             "url": "https://gy-mate.hu/gtfs/gtfs_hu_chairlift.zip",
             "license": {
-                "spdx-identifier": "GPL-3.0-only"
+                "spdx-identifier": "CC-BY-4.0"
             }
         },
         {
@@ -81,7 +81,7 @@
             "type": "http",
             "url": "https://gy-mate.hu/gtfs/gtfs_hu_urom.zip",
             "license": {
-                "spdx-identifier": "GPL-3.0-only"
+                "spdx-identifier": "CC-BY-4.0"
             }
         },
         {