Release branching

Creating a new REL branch
Create the new branch using branch-version.py in the mediawiki/tools/release repository.

simply takes the  version number as an argument:

For example:

Should do the following:


 * 1) Create a new   branch for extensions, skins, and vendor listed in the   bundle under , starting at the tip of the latest WMF-deployed branch (e.g.  ).
 * 2) Branch all remaining extensions and skins for active repos in Gerrit, starting at the tip of.
 * 3) Branch , starting at the tip of the latest WMF-deployed branch.
 * 4) Submits a patchset for review with changes to core:
 * 5) Removing existing submodules that were added prior to WMF deployment.
 * 6) Adding new submodules for every extension/skin in the   bundle from.
 * 7) Setting the   to.