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.

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.

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: I24a681c65c4de50d654f139bc87bc321cb819b22

doc/requirements.txt

@@ -1,3 +1,3 @@
-openstackdocstheme>=1.20.0 # Apache-2.0
-reno>=2.5.0 # Apache-2.0
-sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2 # BSD
+openstackdocstheme>=2.2.0 # Apache-2.0
+reno>=3.1.0 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD

doc/source/conf.py

@@ -48,7 +48,7 @@ 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 --------------------------------------------------
 
@@ -58,6 +58,11 @@ pygments_style = 'sphinx'
 html_theme = 'openstackdocs'
 # html_static_path = ['static']
 
+# openstackdocstheme options
+openstackdocs_repo_name = 'openstack/ironic-prometheus-exporter'
+openstackdocs_pdf_link = True
+openstackdocs_use_storyboard = True
+
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'ironic_prometheus_exporter_doc'
 

releasenotes/source/conf.py

@@ -47,9 +47,8 @@ extensions = [
 ]
 
 
-repository_name = 'openstack/ironic-prometheus-exporter'
-use_storyboard = True
-
+openstackdocs_repo_name = 'openstack/ironic-prometheus-exporter'
+openstackdocs_use_storyboard = True
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
@@ -65,7 +64,6 @@ master_doc = 'index'
 
 # -- Project information -----------------------------------------------------
 
-project = u'Ironic Prometheus Exporter Release Notes'
 copyright = u'2019, Ironic Prometheus Exporter Developers'
 
 # Release notes are version independent.
@@ -104,7 +102,7 @@ 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 = []