Merge branch 'mr-46887-add-docs-for-epic-id' into 'master'

Add epic_id field to issues API documentation

See merge request gitlab-org/gitlab!77510

doc/api/issues.md

@@ -62,6 +62,7 @@ GET /issues?state=opened
 | `created_after`     | datetime         | no         | Return issues created on or after the given time. Expected in ISO 8601 format (`2019-03-15T08:00:00Z`) |
 | `created_before`    | datetime         | no         | Return issues created on or before the given time. Expected in ISO 8601 format (`2019-03-15T08:00:00Z`) |
 | `due_date`          | string           | no         | Return issues that have no due date, are overdue, or whose due date is this week, this month, or between two weeks ago and next month. Accepts: `0` (no due date), `overdue`, `week`, `month`, `next_month_and_previous_two_weeks`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/233420) in GitLab 13.3)_ |
+| `epic_id` **(PREMIUM)** | integer      | no         | Return issues associated with the given epic ID. `None` returns issues that are not associated with an epic. `Any` returns issues that are associated with an epic. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46887) in GitLab 13.6)_
 | `iids[]`            | integer array    | no         | Return only the issues having the given `iid`                                                                                                       |
 | `in`                | string           | no         | Modify the scope of the `search` attribute. `title`, `description`, or a string joining them with comma. Default is `title,description`             |
 | `issue_type`        | string           | no         | Filter to a given type of issue. One of `issue`, `incident`, or `test_case`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/260375) in GitLab 13.12)_ |
@@ -264,6 +265,7 @@ GET /groups/:id/issues?state=opened
 | `created_after`     | datetime         | no         | Return issues created on or after the given time. Expected in ISO 8601 format (`2019-03-15T08:00:00Z`) |
 | `created_before`    | datetime         | no         | Return issues created on or before the given time. Expected in ISO 8601 format (`2019-03-15T08:00:00Z`) |
 | `due_date`          | string           | no         | Return issues that have no due date, are overdue, or whose due date is this week, this month, or between two weeks ago and next month. Accepts: `0` (no due date), `overdue`, `week`, `month`, `next_month_and_previous_two_weeks`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/233420) in GitLab 13.3)_ |
+| `epic_id` **(PREMIUM)** | integer      | no         | Return issues associated with the given epic ID. `None` returns issues that are not associated with an epic. `Any` returns issues that are associated with an epic. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46887) in GitLab 13.6)_
 | `id`                | integer/string   | yes        | The ID or [URL-encoded path of the group](index.md#namespaced-path-encoding) owned by the authenticated user                 |
 | `iids[]`            | integer array    | no         | Return only the issues having the given `iid`                                                                                 |
 | `issue_type`        | string           | no         | Filter to a given type of issue. One of `issue`, `incident`, or `test_case`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/260375) in GitLab 13.12)_ |
@@ -463,6 +465,7 @@ GET /projects/:id/issues?state=opened
 | `created_after`     | datetime         | no         | Return issues created on or after the given time. Expected in ISO 8601 format (`2019-03-15T08:00:00Z`) |
 | `created_before`    | datetime         | no         | Return issues created on or before the given time. Expected in ISO 8601 format (`2019-03-15T08:00:00Z`) |
 | `due_date`          | string           | no         | Return issues that have no due date, are overdue, or whose due date is this week, this month, or between two weeks ago and next month. Accepts: `0` (no due date), `overdue`, `week`, `month`, `next_month_and_previous_two_weeks`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/233420) in GitLab 13.3)_ |
+| `epic_id` **(PREMIUM)** | integer      | no         | Return issues associated with the given epic ID. `None` returns issues that are not associated with an epic. `Any` returns issues that are associated with an epic. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46887) in GitLab 13.6)_
 | `id`                | integer/string   | yes        | The ID or [URL-encoded path of the project](index.md#namespaced-path-encoding) owned by the authenticated user               |
 | `iids[]`            | integer array    | no         | Return only the issues having the given `iid`                                                                              |
 | `issue_type`        | string           | no         | Filter to a given type of issue. One of `issue`, `incident`, or `test_case`. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/260375) in GitLab 13.12)_ |

doc/api/issues_statistics.md

@@ -41,6 +41,7 @@ GET /issues_statistics?confidential=true
 | `author_username`   | string           | no         | Return issues created by the given `username`. Similar to `author_id` and mutually exclusive with `author_id`. |
 | `assignee_id`       | integer          | no         | Return issues assigned to the given user `id`. Mutually exclusive with `assignee_username`. `None` returns unassigned issues. `Any` returns issues with an assignee. |
 | `assignee_username` | string array     | no         | Return issues assigned to the given `username`. Similar to `assignee_id` and mutually exclusive with `assignee_id`. In GitLab CE `assignee_username` array should only contain a single value or an invalid parameter error is returned otherwise. |
+| `epic_id` **(PREMIUM)** | integer      | no         | Return issues associated with the given epic ID. `None` returns issues that are not associated with an epic. `Any` returns issues that are associated with an epic. _([Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46887) in GitLab 13.6)_
 | `my_reaction_emoji` | string           | no         | Return issues reacted by the authenticated user by the given `emoji`. `None` returns issues not given a reaction. `Any` returns issues given at least one reaction. |
 | `iids[]`            | integer array    | no         | Return only the issues having the given `iid`                                                                                                       |
 | `search`            | string           | no         | Search issues against their `title` and `description`                                                                                               |