Links for schemas in README broken

[johanneswerner]

The links in the README file (see below) are all leading to 404 errors.

The schema is also available as:

- JSON Schema
- Protobuf
- GraphQL
- OWL
- ShEx

[turbomam]

Thanks @johanneswerner . There has some reorganization of content between the https://github.com/microbiomedata/nmdc-metadata and https://github.com/microbiomedata/nmdc-schema repositories.

@wdduncan and I are working through it.

While the nmdc-schema README doesn't have links to artifacts like the nmdc-metadata README did, some of the artifacts do appear in subdirectories of the repo, like https://github.com/microbiomedata/nmdc-schema/tree/main/jsonschema

[dwinston]

@turbomam this seems related to microbiomedata/nmdc-schema#84. Perhaps combine them? Alternative, versioned schema representations are also "data objects".