Pin setuptools for pkg stub to v65.6.3

This patch is meant to improve the reproducibility of smoke-testing.

Author: webknjaz

.github/workflows/self-smoke-test-action.yml

@@ -56,8 +56,11 @@ jobs:
       env:
         CONTENTS: |
           [build-system]
-          requires = ["setuptools>=61"]
+          requires = [
+            "setuptools == 65.6.3",
+          ]
           build-backend = "setuptools.build_meta"
+
           [project]
           name = "test-package"
           version = "0.1"