Renaming v4.0.x git branch

[Alan DeKok]

On Jun 12, 2018, at 11:02 AM, Chaigneau, Nicolas <nicolas.chaigneau at capgemini.com> wrote:
> 
> But isn't "master" even better than 4 ? 😃

  We have "4 > 3", but it's harder to see that "master > 3".

> (the default branch on GitHub is master - and was 4.0.x before that, maybe that's why people are using it ?)

  Hmm... that should likely be fixed.

> Note: links in the README.md are now broken (they still point to 4.0.x).

  OK.

  Alan DeKok.