Create Metadata

Create a new metadata item for a revision.

POST `/revisions/:id/metadata/:alias`

Parameter	Type	Required	Description
`id`	string	Yes	The unique ID of the revision.
`alias`	string	Yes	The alias for the new metadata item.

Parameter	Type	Required	Description
`value`	string	No	Arbitrary string value.
`data`	object	No	Arbitrary JSON object.

Parameter	Type	Description
`item_id`	string	The unique ID of the created item.

{
  "value": "approved",
  "data": { "approver": "admin" }
}