docs: update python docs template (#576)

* docs: update python docs template

* sphinx change

Author: kolea2

synthtool/gcp/templates/python_library/docs/conf.py.j2

@@ -38,6 +38,7 @@ extensions = [
     "sphinx.ext.napoleon",
     "sphinx.ext.todo",
     "sphinx.ext.viewcode",
+    "recommonmark",
 ]
 
 # autodoc/autosummary flags
@@ -49,10 +50,6 @@ autosummary_generate = True
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ["_templates"]
 
-# Allow markdown includes (so releases.md can include CHANGLEOG.md)
-# http://www.sphinx-doc.org/en/master/markdown.html
-source_parsers = {".md": "recommonmark.parser.CommonMarkParser"}
-
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 # source_suffix = ['.rst', '.md']

synthtool/gcp/templates/python_library/noxfile.py.j2

@@ -166,7 +166,7 @@ def docs(session):
     """Build the docs for this library."""
 
     session.install('-e', '.')
-    session.install('sphinx<3.0.0', 'alabaster', 'recommonmark')
+    session.install('sphinx', 'alabaster', 'recommonmark')
 
     shutil.rmtree(os.path.join('docs', '_build'), ignore_errors=True)
     session.run(