Replace messageCallback* with app_id

Author: Mark Lewin

numbers/update-number.sh

@@ -6,5 +6,5 @@ curl -X POST \
   "https://rest.nexmo.com/number/update?api_key=$NEXMO_API_KEY&api_secret=$NEXMO_API_SECRET" \
   -H "Content-Type: application/x-www-form-urlencoded" \
   -d "country=$COUNTRY_CODE&msisdn=$NEXMO_NUMBER&moHttpUrl=$SMS_CALLBACK_URL" \
-  -d "&messagesCallbackType=app&messagesCallbackValue=$NEXMO_APPLICATION_ID" \
+  -d "app_id=$NEXMO_APPLICATION_ID" \
   -d "&voiceCallbackType=$VOICE_CALLBACK_TYPE&voiceCallbackValue=$VOICE_CALLBACK_VALUE&voiceStatusCallback=$VOICE_STATUS_URL"