Below is the full update log which should highlight errors as
"Skipped branch ...":

[Composer\Repository\InvalidRepositoryException]: No valid composer.json was found in any branch or tag of git://github.com/cedriclombardot/TwigGenerator.git, could not load a package from it.

Reading composer.json of cedriclombardot/twig-generator (master)
Skipped branch master, Invalid package information:
authors.1.email : invalid value (), must be a valid email address