Switch to openstackdocstheme

oslosphinx has been retired[1] and is no longer compatible with the
latest Sphinx. Use openstackdocstheme instead.

[1] https://review.opendev.org/649070

Change-Id: Idb2fd37dcff7a6fe05d4874134ace49c227a78ae

doc/source/conf.py

@@ -10,7 +10,7 @@ sys.path.insert(0, os.path.abspath('../..'))
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
     'sphinx.ext.autodoc',
-    'oslosphinx',
+    'openstackdocstheme',
 ]
 
 # autodoc generation is a bit aggressive and a nuisance when doing heavy

lower-constraints.txt

@@ -9,7 +9,7 @@ Jinja2==2.10
 linecache2==1.0.0
 MarkupSafe==1.0
 mccabe==0.6.1
-oslosphinx==4.7.0
+openstackdocstheme==1.18.1
 pbr==2.0.0
 pycodestyle==2.3.1
 pyflakes==1.6.0

test-requirements.txt

@@ -5,5 +5,6 @@ stestr>=2.0.0 # Apache-2.0
 testresources>=2.0.0 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 
-sphinx!=1.6.6,!=1.6.7,>=1.6.5 # BSD
-oslosphinx>=4.7.0 # Apache-2.0
+sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
+openstackdocstheme>=1.18.1 # Apache-2.0