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.

Disable openstackdocs_auto_name to use 'project' variable as name.

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: I40301c69287242132b714ed354ee8fd421e1a94c

releasenotes/source/conf.py

@@ -42,13 +42,10 @@ templates_path = ['_templates']
 source_suffix = '.rst'
 
 # openstackdocstheme options
-repository_name = 'openstack/trove-dashboard'
-bug_project = 'trove-dashboard'
-bug_tag = ''
-
-# Must set this variable to include year, month, day, hours, and minutes.
-html_last_updated_fmt = '%Y-%m-%d %H:%M'
-
+openstackdocs_repo_name = 'openstack/trove-dashboard'
+openstackdocs_auto_name = False
+openstackdocs_bug_project = 'trove-dashboard'
+openstackdocs_bug_tag = ''
 
 # The encoding of source files.
 #source_encoding = 'utf-8-sig'
@@ -101,7 +98,7 @@ 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 = []

test-requirements.txt

@@ -7,11 +7,11 @@ coverage>=3.6
 ddt>=0.7.0
 python-subunit>=0.0.18
 selenium>=2.50.1 # Apache-2.0
-sphinx>=1.6.2 # BSD
-openstackdocstheme>=1.17.0 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
+openstackdocstheme>=2.2.1 # Apache-2.0
 testrepository>=0.0.18
 testscenarios>=0.4
 testtools>=1.4.0
 # This also needs xvfb library installed on your OS
 xvfbwrapper>=0.1.3 #license: MIT
-reno>=1.6.2 # Apache2
+reno>=3.1.0 # Apache-2.0