Add 'pet' to Excrement Bag Dispenser terms (#370)

Author: arch0345

data/presets/amenity/vending_machine/excrement_bags.json

@@ -26,7 +26,8 @@
         "poop",
         "waste",
         "dog",
-        "animal"
+        "animal",
+        "pet"
     ],
     "tags": {
         "amenity": "vending_machine",