Missing git tags for 20170523 and 20170413

[ThisIsMissEm]

Please Indicate One:

• Editorial

Please Describe the Issue:

The ActivityStreams Vocabulary document references two versions in it's header: 20170523 and 20170413. These do not appear to be tags on the GitHub repository.

[ThisIsMissEm]

This came up whilst addressing the TODO that was previously at: https://www.w3.org/wiki/Activity_Streams/Primer

[evanp]

It looks like we stopped tagging releases around 2016: https://github.com/w3c/activitystreams/tags . That was probably when @jasnell stepped back and I took over as editor, since there aren't any additional tags afterwards.

We can obviously add these tags in now; finding the right point to do it might be a challenge. Clearly we know the right date, but it might be better to check the commit messages to see when a release came out. Another option is to check against the version still up on the W3C web site.

This seems like an interesting project, so I'll plan to do it async.

[dariusk]

In case it helps, here is a list of commits up to and around the dates implied in the tags

https://github.com/w3c/activitystreams/commits/main/?since=2017-04-01&until=2017-05-31