Trying different reqs

docs/requirements.txt

@@ -2,6 +2,5 @@ cython>=0.20
 numpy>=1.9
 
 # Note: beware of https://github.com/readthedocs/sphinx_rtd_theme/issues/1115
-# and broken behavior with docutils 0.17
-sphinx>=4.3.0
-sphinx-rtd-theme>=0.5.1
+sphinx
+sphinx-rtd-theme>=1.0.0