Bump actions/download-artifact from 7 to 8 in /.github/workflows

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/debug-artifacts-failure-safe.yml

@@ -89,7 +89,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Download all artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
       - name: Check expected artifacts exist
         run: |
           LANGUAGES="cpp csharp go java javascript python"

.github/workflows/debug-artifacts-safe.yml

@@ -83,7 +83,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Download all artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
       - name: Check expected artifacts exist
         run: |
           VERSIONS="stable-v2.20.3 default linked nightly-latest"