Fix release of Sphinx by forcing upgrades to dependencies

This fixes sphinx-doc#9434, and should probably go into a new 4.1.1 release

setup.py

@@ -15,12 +15,12 @@
     sys.exit(1)
 
 install_requires = [
-    'sphinxcontrib-applehelp',
-    'sphinxcontrib-devhelp',
-    'sphinxcontrib-jsmath',
-    'sphinxcontrib-htmlhelp',
-    'sphinxcontrib-serializinghtml',
-    'sphinxcontrib-qthelp',
+    'sphinxcontrib-applehelp>=1.0.2',
+    'sphinxcontrib-devhelp>=1.0.2',
+    'sphinxcontrib-jsmath>=1.0.1',
+    'sphinxcontrib-htmlhelp>=2.0.0',
+    'sphinxcontrib-serializinghtml>=1.1.5',
+    'sphinxcontrib-qthelp>=1.0.3',
     'Jinja2>=2.3',
     'Pygments>=2.0',
     'docutils>=0.14,<0.18',