Fix Nu release packages after upgrading to Nu v0.91

[hustcer]

Description

Fix Nu release packages after upgrading to Nu v0.91
mv fails here: https://github.com/nushell/nightly/actions/runs/8199461348/job/22424601700 with error:

Error: nu::shell::eval_block_with_input

  × Eval block failed with pipeline input
     ╭─[/home/runner/work/nightly/nightly/.github/workflows/release-pkg.nu:158:18]
 157 │ 
 158 │     let files = (ls | get name)
     ·                  ─┬
     ·                   ╰── source value
 159 │     let dest = if $env.RELEASE_TYPE == 'full' { $'($bin)-($version)-($FULL_NAME)' } else { $'($bin)-($version)-($target)' }
     ╰────

Error:   × cannot move '/home/runner/work/nightly/nightly/output/nu' to a
  │ subdirectory of itself, '/home/runner/work/nightly/nightly/output/nu-
  │ 0.91.1-x86_64-unknown-linux-gnu//home/runner/work/nightly/nightly/output/
  │ nu'

Is this a bug of mv? At least the mv command in 0.90.1 works