chore: change oauth token endpoint

Author: tiwarishubham635

lib/twilio-ruby/http/org_token_manager.rb

@@ -19,7 +19,7 @@ def initialize(grant_type, client_id, client_secret, code = nil, redirect_uri =
 
       def fetch_access_token
         client = Twilio::REST::Client.new
-        token_instance = client.iam.v1.token.create(grant_type: @grant_type,
+        token_instance = client.oauth.v2.token.create(grant_type: @grant_type,
                                                     client_id: @client_id, client_secret: @client_secret)
         token_instance.access_token
       end