update .schema.json files for enum string -> integer change

[edwintorok]

enums for bufferView target are integers now 1 2 (and probably some other things), but the schema still uses the strings, which means that the example models don't validate against the provided schema on master.
Please fix the schema files.

[pjcozzi]

Thanks for the report; the schema and spec are behind the converter in several other areas as well. I wouldn't worry about validating against the schema until it is fully updated.

[pjcozzi]

The schema is updated now.