[CI] Benchmark upload broken after action link hardening.

[marcalff]

CI got broken by PR #3338

In particular, this change in benchmark.yaml:

- uses: actions/download-artifact@master
+ uses: actions/download-artifact@2a5974104b6d5dbdb2f9468a3e54da3bdd241578 # master

seem to be the root cause of the break.

Note that, before the fix, a different commit ID was used for download-artifact@master, as seen in runner logs:

Current runner version: '2.323.0'
Operating System
Runner Image
Runner Image Provisioner
GITHUB_TOKEN Permissions
Secret source: Actions
Prepare workflow directory
Prepare all required actions
Getting action download info
Download immutable action package 'actions/checkout@v4'
Download action repository 'actions/download-artifact@master' (SHA:95815c38cf2ff2164869cbab79da8d1f422bc89e)
Download action repository 'benchmark-action/github-action-benchmark@v1' (SHA:d48d326b4ca9ba73ca0cd0d59f108f9e02a381c7)
Complete job name: Store benchmark result (api)

See:

Download action repository 'actions/download-artifact@master' (SHA:95815c38cf2ff2164869cbab79da8d1f422bc89e)

After the change:

Current runner version: '2.323.0'
Operating System
Runner Image
Runner Image Provisioner
GITHUB_TOKEN Permissions
Secret source: Actions
Prepare workflow directory
Prepare all required actions
Getting action download info
Download action repository 'actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683' (SHA:11bd71901bbe5b1630ceea73d27597364c9af683)
Download action repository 'actions/download-artifact@2a5974104b6d5dbdb2f9468a3e54da3bdd241578' (SHA:2a5974104b6d5dbdb2f9468a3e54da3bdd241578)
Download action repository 'benchmark-action/github-action-benchmark@d48d326b4ca9ba73ca0cd0d59f108f9e02a381c7' (SHA:d48d326b4ca9ba73ca0cd0d59f108f9e02a381c7)
Complete job name: Store benchmark result (api)

See:

Download action repository 'actions/download-artifact@2a5974104b6d5dbdb2f9468a3e54da3bdd241578' (SHA:2a5974104b6d5dbdb2f9468a3e54da3bdd241578)

which fails with:

Run actions/download-artifact@2a5974104b6d5dbdb2f9468a3e54da3bdd241578
  with:
    name: benchmark_results
    path: benchmarks
Starting download for benchmark_results
Error: Unable to find any artifacts for the associated workflow