Swap pytest to pytest -s

See why it randomly fails sometimes

.gitlab-ci.yml

@@ -51,7 +51,7 @@ test-intel-py:
     - export PATH=$INTEL_COMP_ROOT/bin/:$INTEL_COMP_ROOT/bin/intel64:$I_MPI_ROOT/bin:$PATH
     - export OMP_NUM_THREADS=2
     - export OMP_PLACES=cores
-    - pytest tests/pytest
+    - pytest -s tests/pytest
 
 test-intel-googletest:
   stage: unit_test
@@ -142,7 +142,7 @@ test-gnu-py:
     - export PYTHONPATH=$HOME/intel/oneapi/intelpython/latest/lib/python3.7/site-packages/:cpp_sisso_env/lib/python3.7/site-packages/
     - export OMP_NUM_THREADS=2
     - export OMP_PLACES=cores
-    - pytest tests/pytest
+    - pytest -s tests/pytest
 
 test-gnu-googletest:
   stage: unit_test