Documentation unclear on how the github-release command works

I was trying to use the command scriv github-release to publish a release, but I haven’t been successful. Every time I try, I get this message:

λ scriv github-release
warning: Version 0.1.0 has no tag. No release will be made.

I tried creating tags for version 0.1.0 in three different ways:

git tag 0.1.0
git tag v0.1.0
git tag -a v0.1.0 -m "My annotation here."

None of these seem to work 🤷

[nedbat]

This is now released as part of scriv 0.16.0.

[nedbat]

I added more explanation in 4f1ceca7bd283484d3f12a6dbc5feb953ec1be2e.