uv

25dd584a - Add a version backwards incompatibility scheme for the JSON Python download list

Add a version backwards incompatibility scheme for the JSON Python download list If the JSON does not deserialize, check to see if any key is named "version" and print a different error message hinting at upgrading uv. The intention is that we will add this field on backwards-incompatible changes (and set it to an integer or string or something else that does not deserialize into a JsonPythonDownload).