Composer — установить github fork / branch

Почему композитор не может установить ветку из https://github.com/wimvds/DoctrineMigrationsBundle/tree/feature/multiple-em-support ?

Мой композитор.json:

"repositories": [
{
"type":"package",
"package": {
"name": "doctrine/doctrine-migrations-bundle",
"version":"master",
"source": {
"url": "https://github.com/wimvds/DoctrineMigrationsBundle.git",
"type": "git",
"reference":"master"}
}
}
],
"require": {
(...)
"doctrine/migrations": "1.0.*@dev",
"doctrine/doctrine-migrations-bundle": "dev-feature/multiple-em-support",
(...)
}.

Ошибка:

composer update

Your requirements could not be resolved to an installable set of packages.

Problem 1
- The requested package doctrine/doctrine-migrations-bundle dev-feature/multiple-em-support could not be found.

Potential causes:
- A typo in the package name
- The package is not available in a stable-enough version according to your minimum-stability setting
see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

Более простой способ без «пакета» сработал:

"repositories": [
{
"url": "https://github.com/wimvds/DoctrineMigrationsBundle.git",
"type": "git"}
],