Use setuptools<66 for Python 3.7

Author: Pavel Minaev

azure-pipelines/templates/run_tests.yml

@@ -5,7 +5,7 @@ steps:
   # tox will automatically install the most recent version of setuptools to build the package.
   # However, for Python 3.7, we want an older version of setuptools to avoid DeprecationWarning
   # for pkg_resources getting triggered by test_gevent.
-  - script: 'python -m pip install -U "setuptools<68"'
+  - script: 'python -m pip install -U "setuptools<66"'
     displayName: "Install setuptools"
     condition: eq(variables['python.version'], '3.7')