meta: bump actions/download-artifact from 7.0.0 to 8.0.0

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 7.0.0 to 8.0.0.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@37930b1...70fc10c)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: 8.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build-tarball.yml

@@ -127,7 +127,7 @@ jobs:
       - name: Environment Information
         run: npx envinfo
       - name: Download tarball
-        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131  # v7.0.0
+        uses: actions/download-artifact@70fc10c6e5e1ce46ad2ea6f2b72d43f7d47b13c3  # v8.0.0
         with:
           name: tarballs
           path: tarballs

.github/workflows/test-shared.yml

@@ -153,7 +153,7 @@ jobs:
     name: '${{ matrix.system }}: with shared libraries'
     runs-on: ${{ matrix.runner }}
     steps:
-      - uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131  # v7.0.0
+      - uses: actions/download-artifact@70fc10c6e5e1ce46ad2ea6f2b72d43f7d47b13c3  # v8.0.0
         if: ${{ github.event_name != 'workflow_dispatch' }}
         with:
           name: tarballs