workflow: Add setuptools as requirement when testing Python 3.12

.github/workflows/ci.yml

@@ -46,7 +46,7 @@ jobs:
       if: matrix.os != 'windows-2019'
       shell: bash
       run: |
-        python -m pip install pytest
+        python -m pip install pytest setuptools
         PYTHONPATH=built LD_LIBRARY_PATH=built/lib DYLD_LIBRARY_PATH=built/lib python -m pytest
 
     - name: Set up Python 3.11

tests/requirements.txt

@@ -1,2 +1,3 @@
 pytest==3.2.0
 panda3d
+setuptools