- In the new multiversion world, python*.inv is in python3.8
directory not python3.

- update to version 3.1.2:
* Incompatible changes
+ #7650: autodoc: the signature of base function will be shown for
decorated functions, not a signature of decorator
* Bugs fixed
+ #7844: autodoc: Failed to detect module when relative module
name given
+ #7856: autodoc: AttributeError is raised when non-class object
is given to the autoclass directive
+ #7850: autodoc: KeyError is raised for invalid mark up when
autodoc_typehints is 'description'
+ #7812: autodoc: crashed if the target name matches to both an
attribute and module that are same name
+ #7650: autodoc: function signature becomes "(*args, **kwargs)"
if the function is decorated by generic decorator
+ #7812: autosummary: generates broken stub files if the target
code contains an attribute and module that are same name
+ #7806: viewcode: Failed to resolve viewcode references on 3rd
party builders
+ #7838: html theme: List items have extra vertical space
+ #7878: html theme: Undesired interaction between "overflow" and
"float"
- changes from version 3.1.1:
* Incompatible changes
+ #7808: napoleon: a type for attribute are represented as typed
field
* Features added