add continuous benchmarking

.github/workflows/continuous_benchmarking.yml

@@ -38,7 +38,7 @@ jobs:
       # Install Python dependencies
       - name: Python dependencies
         run: |
-          python -m pip install --upgrade pip pytest jupyterlab matplotlib pycodestyle scipy pandas
+          python -m pip install --upgrade pip pytest jupyterlab matplotlib pycodestyle scipy pandas pytest-benchmark
           python -m pip install -r requirements.txt
 
       # Install NEST simulator