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.

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: I87335b8494a7b1b3eddd3b6b46b5b5d04227bb6d

doc/source/conf.py

@@ -27,26 +27,13 @@ sys.path.insert(0, os.path.abspath('./'))
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = []
-
-import openstackdocstheme
+extensions = ['openstackdocstheme']
 
 html_theme = 'openstackdocs'
-html_theme_path = [openstackdocstheme.get_html_theme_path()]
 
-# We ask git for the SHA checksum
-# The git SHA checksum is used by "log-a-bug"
-git_cmd = ["/usr/bin/git", "rev-parse", "HEAD"]
-gitsha = str(subprocess.Popen(
-    git_cmd, stdout=subprocess.PIPE).communicate())[0].strip('\n')
-# tag that reported bugs will be tagged with
-bug_tag = "tempest-plugin-docs"
-# source tree
-pwd = os.getcwd()
-# html_context allows us to pass arbitrary values into the html template
-html_context = {"pwd": pwd, "gitsha": gitsha}
-# Must set this variable to include year, month, day, hours, and minutes.
-html_last_updated_fmt = '%Y-%m-%d %H:%M'
+# openstackdocstheme options
+openstackdocs_repo_name = 'openstack/designate-tempest-plugin'
+openstackdocs_bug_tag = "tempest-plugin-docs"
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
@@ -97,7 +84,7 @@ 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 = ["designate_tempest_plugin."]

test-requirements.txt

@@ -4,5 +4,5 @@
 
 # Hacking already pins down pep8/pycodestyle pyflakes and flake8
 hacking>=3.0.1,<3.1.0 # Apache-2.0
-openstackdocstheme>=1.18.1 # Apache-2.0
-sphinx!=1.6.6,!=1.6.7,>=1.6.2  # BSD
+openstackdocstheme>=2.2.1 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD