Switch to newer openstackdocstheme and reno versions

Switch to openstackdocstheme 2.2.0 and reno 3.1.0 versions. Using
these versions will allow especially:
* Linking from HTML to PDF document
* parallelizing building of documents

Update Sphinx version as well.

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.

Set openstackdocs_pdf_link to link to PDF file.

Depends-On: https://review.opendev.org/728938
Change-Id: Ia31f69f00eb24771bf700b4e25ae73a09c1c8aed

doc/requirements.txt

@@ -1,7 +1,7 @@
 # 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.
-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
 sphinxcontrib-svg2pdfconverter>=0.1.0 # BSD

doc/source/conf.py

@@ -63,9 +63,10 @@ sample_config_basename = '_static/tempest'
 todo_include_todos = True
 
 # openstackdocstheme options
-repository_name = 'openstack/tempest'
-bug_project = 'tempest'
-bug_tag = 'doc'
+openstackdocs_repo_name = 'openstack/tempest'
+openstackdocs_bug_project = 'tempest'
+openstackdocs_bug_tag = 'doc'
+openstackdocs_pdf_link = True
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']

releasenotes/source/conf.py

@@ -42,9 +42,9 @@ extensions = [
 ]
 
 # openstackdocstheme options
-repository_name = 'openstack/tempest'
-bug_project = 'tempest'
-bug_tag = ''
+openstackdocs_repo_name = 'openstack/tempest'
+openstackdocs_bug_project = 'tempest'
+openstackdocs_bug_tag = ''
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']