Bump the openstackdocstheme extension to 1.20

Some options are now automatically configured by the version 1.20:
- project
- html_last_updated_fmt
- latex_engine
- latex_elements
- version
- release.

Change-Id: I37a1af868c189c30cc9aa9ee4ca78786ad82d547

doc/requirements.txt

@@ -1,5 +1,5 @@
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
 sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4' # BSD
-openstackdocstheme>=1.18.1  # Apache-2.0
+openstackdocstheme>=1.20.0  # Apache-2.0
 # releasenotes
 reno>=2.5.0 # Apache-2.0

doc/source/conf.py

@@ -43,7 +43,6 @@ copyright = u'2017, OpenStack Developers'
 # openstackdocstheme options
 repository_name = 'openstack/os-resource-classes'
 use_storyboard = True
-html_last_updated_fmt = '%Y-%m-%d %H:%M'
 
 # If true, '()' will be appended to :func: etc. cross-reference text.
 add_function_parentheses = True

releasenotes/source/conf.py

@@ -52,14 +52,12 @@ source_suffix = '.rst'
 master_doc = 'index'
 
 # General information about the project.
-project = u'os_resource_classes Release Notes'
 copyright = u'2017, OpenStack Developers'
 
 # openstackdocstheme options
 repository_name = 'openstack/os-resource-classes'
 bug_project = 'nova'
 bug_tag = ''
-html_last_updated_fmt = '%Y-%m-%d %H:%M'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -197,17 +195,6 @@ htmlhelp_basename = 'os_resource_classesReleaseNotesdoc'
 
 # -- Options for LaTeX output ---------------------------------------------
 
-latex_elements = {
-    # The paper size ('letterpaper' or 'a4paper').
-    # 'papersize': 'letterpaper',
-
-    # The font size ('10pt', '11pt' or '12pt').
-    # 'pointsize': '10pt',
-
-    # Additional stuff for the LaTeX preamble.
-    # 'preamble': '',
-}
-
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).