Doc: Update pip and setuptools when creating the virtual environment (pythonGH-13307)

Add a new pip install before `sphinx` etc.. because we should use the last version of `pip` and `setuptools`

Author: matrixise

Doc/Makefile

@@ -132,6 +132,7 @@ clean:
 
 venv:
 $(PYTHON) -m venv $(VENVDIR)
+$(VENVDIR)/bin/python3 -m pip install -U pip setuptools
 $(VENVDIR)/bin/python3 -m pip install -U Sphinx blurb python-docs-theme
 @echo "The venv has been created in the $(VENVDIR) directory"