chore: update mapboxgl prop

Author: vinayakkulkarni

dist/vue-mapbox-geocoder.common.js

@@ -1992,7 +1992,7 @@ var geocoderEvents = {
       type: Function,
       default: null
     },
-    mapboxGl: {
+    mapboxgl: {
       type: Object,
       default: null
     },

dist/vue-mapbox-geocoder.umd.js

@@ -2001,7 +2001,7 @@ var geocoderEvents = {
       type: Function,
       default: null
     },
-    mapboxGl: {
+    mapboxgl: {
       type: Object,
       default: null
     },