Switch to newer openstackdocstheme and reno versions

Switch to openstackdocstheme 2.2.1 and reno 3.1.0 versions. Using
these versions will allow especially:
* Linking from HTML to PDF document
* Allow parallel building of documents
* Fix some rendering problems

Update Sphinx version as well.

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: I2cad15084abecd4592bb0a2b6d22a75f5713d027

doc/source/conf.py

@@ -53,7 +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 --------------------------------------------------
 
@@ -81,6 +81,7 @@ latex_documents = [
 # intersphinx_mapping = {'http://docs.python.org/': None}
 
 # openstackdocstheme options
-repository_name = 'openstack/tripleo-operator-ansible'
-bug_project = 'tripleo'
-bug_tag = 'documentation'
+openstackdocs_repo_name = 'openstack/tripleo-operator-ansible'
+openstackdocs_auto_name = False
+openstackdocs_bug_project = 'tripleo'
+openstackdocs_bug_tag = 'documentation'

releasenotes/source/conf.py

@@ -88,7 +88,7 @@ exclude_patterns = []
 #show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = 'native'
 
 # A list of ignored prefixes for module index sorting.
 #modindex_common_prefix = []
@@ -264,6 +264,7 @@ texinfo_documents = [
 locale_dirs = ['locale/']
 
 # openstackdocstheme options
-repository_name = 'openstack/tripleo-operator-ansible'
-bug_project = 'tripleo'
-bug_tag = 'documentation'
+openstackdocs_repo_name = 'openstack/tripleo-operator-ansible'
+openstackdocs_auto_name = False
+openstackdocs_bug_project = 'tripleo'
+openstackdocs_bug_tag = 'documentation'

test-requirements.txt

@@ -7,9 +7,8 @@ pre-commit # MIT
 ansible>=2.8
 
 # this is required for the docs build jobs
-sphinx>=1.8.0,<2.0.0;python_version=='2.7' # BSD
-sphinx>=1.8.0,!=2.1.0;python_version>='3.4' # BSD
-openstackdocstheme>=1.29.2 # Apache-2.0
-reno>=2.11.3 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
+openstackdocstheme>=2.2.1 # Apache-2.0
+reno>=3.1.0 # Apache-2.0
 doc8>=0.8.0 # Apache-2.0
 bashate>=0.6.0 # Apache-2.0