Release branch elastix git repository renamed from "master" to "release"

[Niels Dekker]

For your information,

We have just renamed the release branch of https://github.com/SuperElastix/elastix.git from "master" to "release".

If you explicitly refer to this particular branch, you may need to some adjustment at your side. For example, when you locally pulled the "master" branch of elastix, you may need to switch to the "release" branch, as suggested by GitHub:

    git branch -m master release
    git fetch origin
    git branch -u origin/release release
    git remote set-head origin -a

Note that our default branch (for our regular development) is still named "develop", as it was before.

The most important reason for this change is that we think that unnecessary use of the terms "master" and "slave" should be avoided. GitHub has already moved away from using the term "master" last year: https://github.com/github/renaming/blob/main/README.md  I personally felt encouraged by feedback from the #include C++ community: https://www.includecpp.org/resources/language/#master

More details about this change: elastix issue #512, Rename the release branch of elastix git from "master" to "release"