added "special case"

Author: oleg-andreyev

contributing/code/pull_requests.rst

@@ -131,6 +131,13 @@ work:
 
 * ``master``, if you are adding a new feature.
 
+.. note::
+
+    A new **Symfony major version** (e.g. 3.0, 4.0) comes out every *two years*.
+    It is a very special case when new features must go to development branch.
+
+    Check `Symfony Roadmap`_ for latest development branch and not to ``master``
+
 .. note::
 
     All bug fixes merged into maintenance branches are also merged into more
@@ -423,3 +430,4 @@ before merging.
 .. _`Symfony Slack`: https://symfony.com/slack-invite
 .. _`Travis-CI`: https://travis-ci.org/symfony/symfony
 .. _`draft status`: https://help.github.com/en/articles/about-pull-requests#draft-pull-requests
+.. _`Symfony Roadmap`: https://symfony.com/roadmap