The script itself is a part of .travis.yml, using ./scripts/prefix.py
for applying prefixes to the source code.

This purpose of the automatic job is to provide a branch containing
version prefixes, to avoid name conflicts in binaries containing
different major versions of littlefs with only a git clone.

As a part of each release, two branches and a tag are created:
- vN        - moving branch
- vN-prefix - moving branch
- vN.N.N    - immutable tag

The major version branch (vM) is created on major releases, but updated
every patch release. The patch version tag (vM.M.P) is created every
patch release. Patch releases occur every time a commit is merged into
master, though multiple merges may be coalesced.

The major prefix branch (vM-prefix) is modified with the ./scripts/prefix.py
script. Note that this branch is updated as a synthetic merge commit
with the previous history of vM-prefix. The reason for this is to allow
users to easily update vM-prefix with a `git pull` as they would for
other branches.

A---B---C---D---E master, v1, v1.7.3
     \       \   \
      F-------G---H v1-prefix