Fixed test action installation

.gitea/workflows/test_before_merge.yaml

@@ -36,10 +36,12 @@ jobs:
 
       - name: Setting up Python 3.12
         run: |
-          apt install -y python3.12-dev
+          python3.12 -m venv venv
+          source venv/bin/activate
           bash ./install.sh
           bash ./install.sh -dev
 
       - name: Testing with pytest
         run: |
+          source venv/bin/activate
           python3.12 -m pytest