Bump dawidd6/action-download-artifact from 18 to 20 (#749)

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 18 to 20.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](dawidd6/action-download-artifact@v18...v20)

---
updated-dependencies:
- dependency-name: dawidd6/action-download-artifact
  dependency-version: '20'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/comment_benchmarks_v2.yml

@@ -29,7 +29,7 @@ jobs:
           fetch-depth: 0
 
       - name: Download all workflow run artifacts
-        uses: dawidd6/action-download-artifact@v18
+        uses: dawidd6/action-download-artifact@v20
         with:
           github_token: ${{secrets.GITHUB_TOKEN}}
           path: artifacts