Bump actions/upload-artifact from 5 to 6 (#56)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build_image.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Generate SHA256SUM
         run: sha256sum MultiOS-USB_windows_image_*.zip MultiOS-USB_linux_*.tar.gz > sha256sums.txt
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: MultiOS-USB_images_${{ env.ver }}
           path: |