message: fix: for ajv@6 with JSON Schema draft-04
diff: @@ -22,6 +22,8 @@ module.exports = function(json, options) {
  maxFileSize = options.maxFileSize;
  }
  const ajv = new Ajv({
  + schemaId: 'id', // for draft-04
  + meta: false, // don't load draft-07 meta schema
  allErrors: true,
  unknownFormats: true,
  errorDataPath: 'property',
  @@ -39,6 +41,9 @@ module.exports = function(json, options) {
  ajv.removeKeyword('propertyNames');
  ajv.removeKeyword('contains');
  ajv.removeKeyword('const');
  + ajv.removeKeyword('if');
  + ajv.removeKeyword('then');
  + ajv.removeKeyword('else');
  ajv.addKeyword('maxFileSize', {
  validate: function validateMaxFileSize(schema, data) {
  