Adding GCC15 to CI, take 2

Author: gershnik

.github/workflows/test.yml

@@ -100,15 +100,12 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v4
 
-    - name: Setup Python
-      uses: actions/setup-python@v5
-      with:
-        python-version: "3.12"
-
     - name: System Setup
+      shell: bash
       run: |
         apt-get update
         apt-get install -y ninja-build cmake
+        apt-get install -y python3-dev
         if [[ '${{ matrix.module}}' == 'true' ]]; then
             echo "CMAKE_ARGS=-DISPTR_ENABLE_MODULE=ON" >> $GITHUB_ENV
         fi