fix: latest_tag get oldest tag

[fecet]

The current implementation of git.latest_tag seems a bit off. Using -v:refname together with last() is actually selecting the earliest tag, not the latest one.

One can check this by

context:
  git_repo_url: https://github.com/prefix-dev/rattler-build.git
  latest_tag: ${{ git.latest_tag( git_repo_url ) }}

package:
  name: "rattler"
  version: ${{ latest_tag }}

source:
  git: ${{ git_repo_url }}
  tag: ${{ latest_tag }}

[wolfv]

great, thanks!