Switch to newer openstackdocstheme version

Switch to openstackdocstheme 2.2.1 version. Using
this version will allow especially:
* Linking from HTML to PDF document
* Allow parallel building of documents
* Fix some rendering problems

Update Sphinx version as well.

Disable openstackdocs_auto_version to not auto-version the documents.

Change pygments_style to 'native' since old theme version always used
'native' and the theme now respects the setting and using 'sphinx' can
lead to some strange rendering.

openstackdocstheme renames some variables, so follow the renames
before the next release removes them. A couple of variables are also
not needed anymore, remove them.

See also
http://lists.openstack.org/pipermail/openstack-discuss/2020-May/014971.html

Change-Id: I5ff3f372c12db0efeb26737b31006e88ddc238a0

doc/source/conf.py

@@ -36,8 +36,10 @@ project = u'contributor-guide'
 copyright = u'2017, OpenStack Developers'
 
 # openstackdocstheme options
-repository_name = 'openstack/contributor-guide'
-use_storyboard = True
+openstackdocs_repo_name = 'openstack/contributor-guide'
+openstackdocs_auto_name = False
+openstackdocs_auto_version = False
+openstackdocs_use_storyboard = True
 
 # No need to show a version number
 version = ''
@@ -51,7 +53,7 @@ add_function_parentheses = True
 add_module_names = True
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = 'native'
 
 # -- Options for HTML output --------------------------------------------------
 

test-requirements.txt

@@ -2,6 +2,6 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-sphinx!=1.6.6,!=1.6.7,>=1.6.2  # BSD
-openstackdocstheme>=1.28.0  # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
+openstackdocstheme>=2.2.1 # Apache-2.0
 doc8>=0.6.0  # Apache-2.0