Bump rhysd/github-action-benchmark from 1.19.3 to 1.20.4

Bumps [rhysd/github-action-benchmark](https://github.com/rhysd/github-action-benchmark) from 1.19.3 to 1.20.4.
- [Release notes](https://github.com/rhysd/github-action-benchmark/releases)
- [Changelog](https://github.com/benchmark-action/github-action-benchmark/blob/master/CHANGELOG.md)
- [Commits](benchmark-action/github-action-benchmark@cc9ac13...d48d326)

---
updated-dependencies:
- dependency-name: rhysd/github-action-benchmark
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/benchmarks.yaml

@@ -47,7 +47,7 @@ jobs:
         run: cargo bench --bench track -- --output-format bencher | grep -v 'Gnuplot not found' | tee benches.out
 
       - name: Compare benchmarks
-        uses: rhysd/github-action-benchmark@cc9ac13ce81036c9b67fcfe2cb95ca366684b9ea
+        uses: rhysd/github-action-benchmark@d48d326b4ca9ba73ca0cd0d59f108f9e02a381c7
         with:
           name: Track benchmarks
           tool: cargo