`files` directory created in target root on `composer udpate`

[theAverageDev (Luca Tumedei)]

When running the following commands:

cd my-project/plugins
tric here && tric use the-events-calendar
tric composer install
tric run views_widget

Then a files directory is created in the target, the-events-calendar plugin in this example, root directory.
The directory seems to be created by the volume binding of the tests.

[Matthew Batchelder]

Resolved as of 1.1.1!