enum aliases can not be deserialized

[julianskartor]

E.g for

enum ImageType {
  UNSPECIFIED = 0;
  JPEG = 1;
  jpeg = 1;
  PNG = 2;
  png = 2;
}

pbjson_build produces

fn visit_str<E>(self, value: &str) -> std::result::Result<Self::Value, E>
where
    E: serde::de::Error,
{
    match value {
        "UNSPECIFIED" => Ok(ImageType::Unspecified),
        "JPEG" => Ok(image::Type::Jpeg),
        "PNG" => Ok(image::Type::Png),
        _ => Err(serde::de::Error::unknown_variant(value, FIELDS)),
    }
}

and the lower case values jpeg and png can not be deserialized.