Client specification: point changelog to tags, add maintainer note

[mebeim]

This converts the links in the changelog of the client spec to point to version tags instead of commit hashes as suggested by @bl-ue in #5428, and also includes a maintainer note in the form of a comment for future reference when updating the changelog.

I've already pushed the tags from v1.0 to v1.5, which should be visible to everyone here.

[bl-ue]

Also see my comment here: #5428 (comment)

[mebeim]

Quoting your comment from #5428 just to keep the discussion here:

Hmm...I didn't get notified about this. @mebeim I think we need to create an actual release, not just a tag thinking

I actually get GH notifications when I'm watching a repository and they create a release. For example, I was notified when https://github.com/kubernetes/kubernetes/releases/tag/v1.20.5 was released.

Makes sense. I should add this to the maintainer note in the comment then. Should we go ahead and just create a v1.5 release? Previous versions don't strictly need an actual release, but we could do that too.

[bl-ue]

Yes, I think we should. 👍🏻 No one needs to be notified about previous spec versions because the changes made in v1.0-1.4 are incorporated into v1.5.

[mebeim]

Done and done 👍

[sbrl]

Is there anything else specific that needs doing after we merge this?

[bl-ue]

I don't think so, @sbrl. 👍🏻