revert to num-parallel = 8 in test_preparation

Signed-off-by: dafnapension <dafnashein@yahoo.com>

Author: dafnapension

.github/workflows/catalog_preparation.yml

@@ -27,7 +27,7 @@ jobs:
 
     strategy:
       matrix:
-        modulo: [0,1,2,3,4,5,6,7,8,9,10,11]
+        modulo: [0,1,2,3,4,5,6,7]
 
     steps:
     - uses: actions/checkout@v5
@@ -53,7 +53,7 @@ jobs:
       run: |
         modulo="${{ matrix.modulo }}"
         echo "modulo=${modulo}" >> $GITHUB_STEP_SUMMARY
-        echo "sed -i 's/^num_par = 1 /num_par = 12 /' tests/catalog/test_preparation.py" > sedit.sh
+        echo "sed -i 's/^num_par = 1 /num_par = 8 /' tests/catalog/test_preparation.py" > sedit.sh
         echo "sed -i 's/^modulo = 0/modulo = ${modulo}/' tests/catalog/test_preparation.py" >> sedit.sh
         sh sedit.sh
         python -m unittest tests.catalog.test_preparation