fix typo in ci

Author: JavierCladellas

.github/workflows/benchmark.yml

@@ -215,7 +215,7 @@ jobs:
             -   name: Render docs
                 run: |
                     source .venv/bin/activate
-                    render-benchmarks --config_file=./tmp/website_config.json
+                    render-benchmarks --config-file=./tmp/website_config.json
             -   name: Compile docs
                 run: |
                     source .venv/bin/activate