CI fails with the new schema

[ee7]

See for example: #1689

exercises/grade-school/canonical-data.json invalid
[
  {
    keyword: 'additionalProperties',
    dataPath: '.cases[2]',
    schemaPath: '#/additionalProperties',
    params: { additionalProperty: 'reimplements' },
    message: 'should NOT have additional properties'
  },
  {
    keyword: 'additionalProperties',
    dataPath: '.cases[2]',
    schemaPath: '#/additionalProperties',
    params: { additionalProperty: 'uuid' },
    message: 'should NOT have additional properties'
  },
  {
    keyword: 'oneOf',
    dataPath: '.cases[2]',
    schemaPath: '#/oneOf',
    params: {},
    message: 'should match exactly one schema in oneOf'
  }
]