Release branching

Creating a new REL branch

Create the new branch using branch-version.py in the repos/releng/release repository.

branch-version.py simply takes the [major].[minor].[patch] version number as an argument:

For example:

$ ./branch-version.py 1.34.0

Should do the following:

1. Create a new REL1_34 branch for extensions, skins, and vendor listed in the wmf bundle under settings.yaml, starting at the tip of the latest WMF-deployed branch (e.g. wmf/1.34.0-wmf.25).
2. Branch all remaining extensions and skins for active repos in Gerrit, starting at the tip of origin/master.
3. Branch mediawiki/core, starting at the tip of the latest WMF-deployed branch.
4. Submits a patchset for review with changes to core:
   1. Removing existing submodules that were added prior to WMF deployment.
   2. Adding new submodules for every extension/skin in the base bundle from settings.yaml.
   3. Setting the $wgVersion to [version]-rc.0.