Fix build arg of BUILD_REF for docker Images

Author: hustcer

.github/workflows/release-nu-image.yaml

@@ -25,6 +25,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           ref: main
+          fetch-depth: 0
 
       - name: Set up Nushell
         uses: hustcer/setup-nu@v3
@@ -47,11 +48,14 @@ jobs:
       - name: "Set tag & labels for ${{ github.ref }}"
         shell: nu {0}
         run: |
-          $'BUILD_REF=(git rev-parse --short HEAD)(char nl)' o>> $env.GITHUB_ENV
-          $'BUILD_DATE=(date now | format date %Y-%m-%dT%H:%M:%SZ)(char nl)' o>> $env.GITHUB_ENV
           let tagName = http get https://api.github.com/repos/nushell/nushell/releases
                           | sort-by -r created_at | select tag_name | get tag_name.0
+          git remote set-url origin https://github.com/nushell/nushell.git
+          git fetch origin --tags
+          let SHA = git rev-list -n 1 $tagName | str substring 0..7
+          $'BUILD_REF=($SHA)(char nl)' o>> $env.GITHUB_ENV
           $'NU_VERSION=($tagName)(char nl)' o>> $env.GITHUB_ENV
+          $'BUILD_DATE=(date now | format date %Y-%m-%dT%H:%M:%SZ)(char nl)' o>> $env.GITHUB_ENV
 
       - name: Build and Push Debian Image
         uses: docker/build-push-action@v6