don't strictly rely on github releases to tag with dispatch-releases

[Gankra]

The dispatch-releases feature implicitly relies on the fact that GitHub Releases automatically creates a tag if you ask it to create a GitHub Release for a given tag name, which we do.

However when only hosting with axo Releases, that means we won't create a tag at all. Conceptually this is an easy fix. Just add the following here:

https://github.com/axodotdev/cargo-dist/blob/c1526bc57ce4da5c33fa31072ae3bdcd96f7dc94/cargo-dist/templates/ci/github/release.yml.j2#L593

    {{%- elif workflow_dispatch or release_branch %}}
      # TODO: if github releases are disabled AND we're using a non-tag-first workflow,
      # then we're responsible for creating and pushing the tag!
      - name: "tag commit"
        run: |
          git tag ${{ needs.plan.outputs.tag }}
          git push origin tag ${{ needs.plan.outputs.tag }}
    {{%- endif %}}

But the exact details of how we invoke git here might want to be refined.

[Gankra]

note that this needs to be aware of https://opensource.axo.dev/cargo-dist/book/reference/config.html#github-releases-repo