Fix additional lint errors

[kurtmckee]

This PR introduces the following changes:

• Update the schema ID in two additional places; the update in the schema resolves a lint error.
• Update a schema definition reference (require_any -> require_any_field), which resolves a lint error.

The JSON example file is now linted but has the following errors:

[
  {
    instancePath: '/properties/cmip6:index_node',
    schemaPath: '#/definitions/fields/properties/cmip6%3Aindex_node/type',
    keyword: 'type',
    params: { type: 'string' },
    message: 'must be string'
  },
  {
    instancePath: '/properties/cmip6:pid',
    schemaPath: '#/definitions/fields/properties/cmip6%3Apid/type',
    keyword: 'type',
    params: { type: 'string' },
    message: 'must be string'
  },
  {
    instancePath: '/properties/cmip6:levels',
    schemaPath: '#/definitions/fields/properties/cmip6%3Alevels/type',
    keyword: 'type',
    params: { type: 'string' },
    message: 'must be string'
  },
  {
    instancePath: '',
    schemaPath: '#/oneOf',
    keyword: 'oneOf',
    params: { passingSchemas: null },
    message: 'must match exactly one schema in oneOf'
  }
]

These are caused by the following null values in the JSON example:

{
  "cmip6:index_node": null,
  "cmip6:pid": null,
  "cmip6:levels": null
}

I don't know if these should be nullable fields in the schema or values should be updated in the JSON example, so this is as far as I've gotten.