Merge pull request #9051 from soltanmm-google/I-used-to-hate-history-class,then-I-learned-for-myself-that-so-long-as-we're-all-human-we-will-make-the-same-human-mistakes-again-and-again-and-that's-worth-studying

Backport Python setuptools unpinning

tools/run_tests/build_python.sh

@@ -170,8 +170,7 @@ pip_install_dir() {
 }
 
 $VENV_PYTHON -m pip install --upgrade pip
-# TODO(https://github.com/pypa/setuptools/issues/709) get the latest setuptools
-$VENV_PYTHON -m pip install setuptools==25.1.1
+$VENV_PYTHON -m pip install setuptools
 $VENV_PYTHON -m pip install cython
 pip_install_dir $ROOT
 $VENV_PYTHON $ROOT/tools/distrib/python/make_grpcio_tools.py