message: docs: add documentation for record.updateRecord
diff: - [getRecord](#getRecord)
  - [addRecord](#addRecord)
  +- [updateRecord](#updateRecord)
  ## Overview
  @@ -66,3 +67,29 @@ Adds 1 record to an App.
  #### Reference
  - https://developer.kintone.io/hc/en-us/articles/212494628
  +
  +### updateRecord
  +
  +Updates details of 1 record in an App by specifying its record number, or a different unique key.
  +
  +#### Parameters
  +
  +| Name | Type | Required | Description |
  +| --------------- | :--------------: | :-------------------------: | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
  +| app | Number or String | Yes | The App ID. |
  +| id | Number or String | Conditionally<br />Required | The Record ID of the record to be updated. Required, if `updateKey` will not be specified. |
  +| updateKey | Object | Conditionally<br />Required | The unique key of the record to be updated. Required, if `id` will not be specified. To specify this field, the field must have the "Prohibit duplicate values" option turned on. |
  +| updateKey.field | String | Conditionally<br />Required | The field code of the unique key.<br />Required, if `updateKey` will be specified. |
  +| updateKey.value | Number or String | Conditionally<br />Required | The value of the unique key.<br />Required, if `updateKey` will be specified. |
  +| revision | Number or String | | The expected revision number. If the value does not match, an error will occur and the record will not be updated. If the value is not specified or is -1, the revision number will not be checked. |
  +| record | Object | | Field codes and values are specified in this object. If ignored, the record will not be updated. For field type specs, check the [Field Types](https://developer.kintone.io/hc/en-us/articles/212494818/) page. |
  +
  +#### Returns
  +
  +| Name | Type | Description |
  +| -------- | :----: | ---------------------------------- |
  +| revision | String | The revision number of the record. |
  +
  +#### Reference
  +
  +- https://developer.kintone.io/hc/en-us/articles/213149027
  