Specify culture when serializing data

[janousek]

You must specify a culture when calling the ToString method on a numeric type. There are different decimal separators in different countries and when you do not specify culture, national culture is used. This results in unexpceted format of request. The main problem for me is serialization of maxPrice: https://github.com/twilio/twilio-csharp/blob/c2e2430e97c5e49504dba4a3d5f82c093628040d/src/Twilio/Rest/Api/V2010/Account/MessageOptions.cs#L139

In Czech culture (cs-CZ) the nember is serialized as: "0,58" and not like "0.58" as expected.

[childish-sambino]

This issue has been added to our internal backlog to be prioritized. Pull requests and +1s on the issue summary will help it move up the backlog.