[BUGFIX] Support composer ``replace`` directive
Packages that are required but were replaced by using ``replace`` (see
https://getcomposer.org/doc/04-schema.md#replace) in ``composer.json``
would to load with Flow as the replaced package would have no name
in the package map.
Ignoring the dependency is no problem as we do not use it anywhere
where replaced packages could be important.
This is a bugfix that should be replaced with a more robust solution in
a future Flow version. For example by not trying to match composer
requirements to Flow packages.
Releases: master, 3.0, 2.3