tests: install pkg-resoures in workflows

workaround for #2569

Author: sebix

.github/workflows/unittests.yml

@@ -52,6 +52,10 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
 
+    - name: Install setuptools for pkg_resources for Python 3.12+, #2569
+      if: ${{ matrix.python-version >= '3.12' }}
+      run: pip install 'setuptools<82'
+
     - name: Install dependencies for full run
       if: ${{ matrix.type == 'full' }}
       env: