feat(error): allow ErrorKind to be compared

[aidant]

The ErrorKind enum does not implement the PartialEq trait which makes for simple comparisons on the error_response.kind() function tedious. With this change the following becomes possible:

impl From<resend_rs::Error> for Error {
    fn from(value: resend_rs::Error) -> Self {
        match value {
            resend_rs::Error::Resend(error_response)
                if error_response.kind() == resend_rs::types::ErrorKind::InvalidToAddress =>
            {
                todo!()
            }
            _ => todo!(),
        }
    }
}

[AntoniosBarotsis]

@aidant
Thanks for bringing this up! v0.11.2 just got published with this change. Let me know if you encounter any other issues!