use system python instead of github actions python

.github/workflows/debian.yml

@@ -17,16 +17,16 @@ jobs:
           submodules: true
           fetch-depth: 1
 
-      - name: Set up Python
-        uses: actions/setup-python@v1
-        with:
-          python-version: 3.9
-          architecture: x64
+      # - name: Set up Python
+      #   uses: actions/setup-python@v1
+      #   with:
+      #     python-version: 3.9
+      #     architecture: x64
 
       - name: Install packaging dependencies
         run: |
           sudo apt install -y python3 python3-dev python3-pip python3-venv python3-all dh-python debhelper devscripts dput software-properties-common python3-distutils python3-setuptools python3-wheel python3-stdeb
-          pip3 install --upgrade pip setuptools wheel stdeb
+          # pip3 install --upgrade pip setuptools wheel stdeb
 
       - name: Build Debian/Apt sdist_dsc
         run: |