meta: Add explict branch to git SRC_URIs, handle github url changes

meta: Add explict branch to git SRC_URIs, handle github url changes

This update was made with the convert-scruri.py script in scripts/contrib

This script handles two emerging issues:

    1. There is uncertainty about the default branch name in git going forward.
    To try and cover the different possible outcomes, add branch names to all
    git:// and gitsm:// SRC_URI entries.

    2. Github are dropping support for git:// protocol fetching, so remap github
     urls as needed. For more details see:

    https://github.blog/2021-09-01-improving-git-protocol-security-github/

Signed-off-by: Steve Sakoman <steve@sakoman.com>