Add target as required property for Reject in the Activity Vocabulary

[cristianolongoodhl]

See also w3c/activitystreams#534

In https://www.w3.org/TR/activitystreams-vocabulary/#dfn-remove neither origin or target are mentioned

[evanp]

First, almost no properties are "required" in AS2. I think name or summary are the closest thing to required properties.

Second, are you talking about Reject or Remove? You use different activities in the title and in the text of this issue.

[evanp]

We do have required properties in ActivityPub, and Remove has a required target, but not Reject. I'm going to move this issue to the AP repo, for further discussion.

[cristianolongoodhl]

Sorry, I updated the issue title

[cristianolongoodhl]

Sorry again, it was the wrong repository for this issue.