API: Add ability to POST a new tag to /refs/tags

I'm that this doesn't already exist, but it seems that tags via the API are GET only. I want to setup our Octopus Deploy such that it adds a version tag to repos when they move into the production environment. However, without an endpoint to POST a new tag, the only alternative is to setup a full-fledged git situation as a step in our Octopus process, which is way overkill just to be able to push a tag to a commit.