[IMP] conf: vendor python inventories

Reaching external ressources while running tests is an important source
of random error and can even causes deterministic errors when a service
is down for a while.

Runbot will soon block all external requests, this commit follows
changes introduced in #13669 and vendors the python inventories.

closes odoo/documentation#13752

Signed-off-by: Xavier Dollé (xdo) <xdo@odoo.com>

conf.py

@@ -212,7 +212,7 @@ extensions.append('sphinx.ext.graphviz' if shutil.which('dot') else 'graphviz_pl
 todo_include_todos = False
 
 intersphinx_mapping = {
-    'python': ('https://docs.python.org/3/', None),
+    'python': ('https://docs.python.org/3/', '../invs/python.inv'),
     # apparently local inventories are relative to the source dir?
     'werkzeug': ('https://werkzeug.palletsprojects.com/', '../invs/werkzeug.inv'),
 }