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.

Set openstackdocs_pdf_link to link to PDF file. Note that
the link to the published document only works on docs.openstack.org
where the PDF file is placed in the top-level html directory. The
site-preview places the PDF in a pdf directory.

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: Iedbe8c96c57403d5ee7208cc89bddd9809b70eb2

doc/requirements.txt

@@ -1,13 +1,13 @@
 # The order of packages is significant, because pip processes them in the order
 # 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,!=2.1.0 # BSD
+sphinx>=2.0.0,!=2.1.0 # BSD
 sphinx-feature-classification>=0.2.0 # Apache-2.0
-openstackdocstheme>=1.31.2 # Apache-2.0
+openstackdocstheme>=2.2.1 # Apache-2.0
 cliff>=2.14
 
 # releasenotes
-reno>=2.5.0 # Apache-2.0
+reno>=3.1.0 # Apache-2.0
 
 # redirect tests in docs
 whereto>=0.3.0 # Apache-2.0

doc/source/conf.py

@@ -30,7 +30,7 @@ project = u'osc-placement'
 copyright = u'2016, OpenStack Foundation'
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = 'native'
 
 # -- Options for HTML output --------------------------------------------------
 
@@ -46,8 +46,10 @@ autoprogram_cliff_ignored = [
     '--print-empty', '--prefix', '--noindent', '--quote']
 
 # openstackdocstheme options
-repository_name = 'openstack/osc-placement'
-use_storyboard = True
+openstackdocs_repo_name = 'openstack/osc-placement'
+openstackdocs_pdf_link = True
+openstackdocs_auto_name = False
+openstackdocs_use_storyboard = True
 
 # -- Options for LaTeX output -------------------------------------------------
 

releasenotes/source/conf.py

@@ -63,5 +63,6 @@ version = ''
 html_theme = 'openstackdocs'
 
 # openstackdocstheme options
-repository_name = 'openstack/osc-placement'
-use_storyboard = True
+openstackdocs_repo_name = 'openstack/osc-placement'
+openstackdocs_auto_name = False
+openstackdocs_use_storyboard = True