Bump actions/download-artifact from 7 to 8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 7 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v7...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/bench.yml

@@ -134,13 +134,13 @@ jobs:
         enable-stack: false
 
     - name: Download cabal home
-      uses: actions/download-artifact@v7
+      uses: actions/download-artifact@v8
       with:
         name: cabal-home-${{ matrix.ghc }}-${{ matrix.os }}
         path: .
 
     - name: Download workspace
-      uses: actions/download-artifact@v7
+      uses: actions/download-artifact@v8
       with:
         name: workspace-${{ matrix.ghc }}-${{ matrix.os }}
         path: .