minor symfony#10723 Switch to 3.4 as oldest maintained branch (jvasseur)

This PR was merged into the 3.4 branch.

Discussion
----------

Switch to 3.4 as oldest maintained branch

2.8 is now in security fix only mode so this replaces mentions of the 2.8 branch with the 3.4 branch in contributing docs.

Commits
-------

ca423ee Switch to 3.4 as oldest maintained branch

Author: javiereguiluz

README.markdown

@@ -7,8 +7,8 @@ Contributing
 ------------
 
 >**Note**
->Unless you're documenting a feature that was introduced *after* Symfony 2.8
->(e.g. in Symfony 3.4), all pull requests must be based off of the **2.8** branch,
+>Unless you're documenting a feature that was introduced *after* Symfony 3.4
+>(e.g. in Symfony 4.2), all pull requests must be based off of the **3.4** branch,
 >**not** the master or older branches.
 
 We love contributors! For more information on how you can contribute to the

contributing/code/patches.rst

@@ -106,7 +106,7 @@ Choose the right Branch
 Before working on a patch, you must determine on which branch you need to
 work:
 
-* ``2.8``, if you are fixing a bug for an existing feature or want to make a
+* ``3.4``, if you are fixing a bug for an existing feature or want to make a
   change that falls into the :doc:`list of acceptable changes in patch versions
   </contributing/code/maintenance>` (you may have to choose a higher branch if
   the feature you are fixing was introduced in a later version);
@@ -117,7 +117,7 @@ work:
 
     All bug fixes merged into maintenance branches are also merged into more
     recent branches on a regular basis. For instance, if you submit a patch
-    for the ``2.8`` branch, the patch will also be applied by the core team on
+    for the ``3.4`` branch, the patch will also be applied by the core team on
     the ``master`` branch.
 
 Create a Topic Branch
@@ -130,18 +130,18 @@ topic branch:
 
     $ git checkout -b BRANCH_NAME master
 
-Or, if you want to provide a bugfix for the ``2.8`` branch, first track the remote
-``2.8`` branch locally:
+Or, if you want to provide a bugfix for the ``3.4`` branch, first track the remote
+``3.4`` branch locally:
 
 .. code-block:: terminal
 
-    $ git checkout -t origin/2.8
+    $ git checkout -t origin/3.4
 
-Then create a new branch off the ``2.8`` branch to work on the bugfix:
+Then create a new branch off the ``3.4`` branch to work on the bugfix:
 
 .. code-block:: terminal
 
-    $ git checkout -b BRANCH_NAME 2.8
+    $ git checkout -b BRANCH_NAME 3.4
 
 .. tip::
 
@@ -245,7 +245,7 @@ while to finish your changes):
 
 .. tip::
 
-    Replace ``master`` with the branch you selected previously (e.g. ``2.8``)
+    Replace ``master`` with the branch you selected previously (e.g. ``3.4``)
     if you are working on a bugfix
 
 When doing the ``rebase`` command, you might have to fix merge conflicts.
@@ -272,8 +272,8 @@ You can now make a pull request on the ``symfony/symfony`` GitHub repository.
 
 .. tip::
 
-    Take care to point your pull request towards ``symfony:2.8`` if you want
-    the core team to pull a bugfix based on the ``2.8`` branch.
+    Take care to point your pull request towards ``symfony:3.4`` if you want
+    the core team to pull a bugfix based on the ``3.4`` branch.
 
 To ease the core team work, always include the modified components in your
 pull request message, like in:
@@ -344,7 +344,7 @@ Rework your Patch
 
 Based on the feedback on the pull request, you might need to rework your
 patch. Before re-submitting the patch, rebase with ``upstream/master`` or
-``upstream/2.8``, don't merge; and force the push to the origin:
+``upstream/3.4``, don't merge; and force the push to the origin:
 
 .. code-block:: terminal
 

contributing/documentation/overview.rst

@@ -112,14 +112,14 @@ memorable name for the new branch (if you are fixing a reported issue, use
 
 .. code-block:: terminal
 
-    $ git checkout -b improve_install_article upstream/2.8
+    $ git checkout -b improve_install_article upstream/3.4
 
 In this example, the name of the branch is ``improve_install_article`` and the
-``upstream/2.8`` value tells Git to create this branch based on the ``2.8``
+``upstream/3.4`` value tells Git to create this branch based on the ``3.4``
 branch of the ``upstream`` remote, which is the original Symfony Docs repository.
 
 Fixes should always be based on the **oldest maintained branch** which contains
-the error. Nowadays this is the ``2.8`` branch. If you are instead documenting a
+the error. Nowadays this is the ``3.4`` branch. If you are instead documenting a
 new feature, switch to the first Symfony version that included it, e.g.
 ``upstream/3.1``. Not sure? That's ok! Just use the ``upstream/master`` branch.
 
@@ -155,7 +155,7 @@ changes should be applied:
    :align: center
 
 In this example, the **base fork** should be ``symfony/symfony-docs`` and
-the **base** branch should be the ``2.8``, which is the branch that you selected
+the **base** branch should be the ``3.4``, which is the branch that you selected
 to base your changes on. The **head fork** should be your forked copy
 of ``symfony-docs`` and the **compare** branch should be ``improve_install_article``,
 which is the name of the branch you created and where you made your changes.
@@ -205,7 +205,7 @@ contribution to the Symfony docs:
     # create a new branch based on the oldest maintained version
     $ cd projects/symfony-docs/
     $ git fetch upstream
-    $ git checkout -b my_changes upstream/2.8
+    $ git checkout -b my_changes upstream/3.4
 
     # ... do your changes
 
@@ -288,8 +288,8 @@ into multiple branches, corresponding to the different versions of Symfony itsel
 The ``master`` branch holds the documentation for the development branch of
 the code.
 
-Unless you're documenting a feature that was introduced after Symfony 2.8,
-your changes should always be based on the ``2.8`` branch. Documentation managers
+Unless you're documenting a feature that was introduced after Symfony 3.4,
+your changes should always be based on the ``3.4`` branch. Documentation managers
 will use the necessary Git-magic to also apply your changes to all the active
 branches of the documentation.