Log Message:
asdf: update to 0.15.0. Changes:

- correct description for version preceded by star
- golang-rewrite: remove `asdf update` command to prepare for Go version
- completions: Address two Bash completion bugs
- make plugin-test work on alpine linux
- nushell: nushell spread operator
- nushell: Use correct env var for shims dir
- when download path got removed, it should use -f to force delete the
  download files

Updating this leaf package during the freeze for the bug and
portability fixes.