Merge pull request #3230 from brianmaissy/features

deprecate pytest_plugins in non-top-level conftest

doc/en/plugins.rst

@@ -80,6 +80,12 @@ will be loaded as well.
 
 which will import the specified module as a ``pytest`` plugin.
 
+.. note::
+    Requiring plugins using a ``pytest_plugins`` variable in non-root
+    ``conftest.py`` files is deprecated. See
+    :ref:`full explanation <requiring plugins in non-root conftests>`
+    in the Writing plugins section.
+
 .. _`findpluginname`:
 
 Finding out which plugins are active