Link readme to the default / stable documentation not latest

It doesn't seem like you can deep link into the default? Not entirely
clear, I'll probably have to read up on rtfd redirections but that's
probably fine for now.

Author: masklinn

README.rst

@@ -12,7 +12,7 @@ Build Status
    :alt: CI on the master branch
 
 .. image:: https://readthedocs.org/projects/uap-python/badge/?version=latest
-   :target: https://uap-python.readthedocs.io/en/latest/
+   :target: https://uap-python.readthedocs.io/
    :alt: Documentation Status
 
 Installing
@@ -42,7 +42,7 @@ ua-parser supports CPython 3.9 and newer, recent pypy (supporting
    See `builtin resolvers`_ for more explanation of the tradeoffs
    between the different options.
 
-.. _builtin resolvers: https://uap-python.readthedocs.io/en/latest/guides.html#builtin-resolvers
+.. _builtin resolvers: https://uap-python.readthedocs.io/stable/guides.html#builtin-resolvers
 
 Quick Start
 -----------
@@ -114,4 +114,4 @@ Upgrading
 
 Upgrading from 0.x? See `the upgrade guide`_.
 
-.. _the upgrade guide: https://uap-python.readthedocs.io/en/latest/advanced/migration.html
+.. _the upgrade guide: https://uap-python.readthedocs.io/stable/advanced/migration.html