Nexmo Ruby v7.0.0 Release

The Nexmo Ruby SDK has released version 7.0.0 with improved API error handling, renamed the `Calls` class to `Voice`, and introduced static typing for the `Account`, `Alerts`, and SMS classes, making it easier for developers to handle errors and write more robust code. The new release aims to improve consistency across languages and provide a better experience for users. The SDK continues to evolve with upcoming features like the Conversations, Messages, and Dispatch APIs, and developers are encouraged to contribute to the GitHub repository or join the Nexmo Community Slack.