fix Kazakhstan dial_code

Author: 4ndrey

MRCountryPicker/Assets/SwiftCountryPicker.bundle/Data/countryCodes.json

@@ -546,7 +546,7 @@
 },
 {
 "name": "Kazakhstan",
-"dial_code": "+77",
+"dial_code": "+7",
 "code": "KZ"
 },
 {