[DNM] Testing docs bump with new Sphinx

Sphinx updates can be scary.  This change leverages a constraints bump to see what breaks.

Depends-On: https://review.opendev.org/c/openstack/requirements/+/916565
Change-Id: I1a8f7c86940e25206346db8b46ed17167a8c44c1

doc/requirements.txt

@@ -10,3 +10,4 @@ mock>=2.0.0 # BSD
 ddt>=1.0.1 # MIT
 testtools>=2.2.0 # MIT
 tempest>=17.1.0 # Apache-2.0
+# Force docs rebuild: 

requirements.txt

@@ -26,3 +26,4 @@ paramiko>=2.7.1 # LGPLv2.1+
 
 apscheduler>=3.0.5 # MIT License
 psutil>=3.2.2 # BSD
+# Force requirements rebuild: 

setup.py

@@ -27,3 +27,5 @@ except ImportError:
 setuptools.setup(
     setup_requires=['pbr>=2.0.0'],
     pbr=True)
+
+# Force unittests: