Deprecation warning on ProjectLayout.configurableFiles()

[clemstoquart]

Hi guys,

I have the following deprecation warning message with the release 0.6 and Gradle 5.4.1 :

> Configure project :
The ProjectLayout.configurableFiles() method has been deprecated. This is scheduled to be removed in Gradle 6.0. Please use the ObjectFactory.fileCollection() method instead.

I'll try to provide a PR shortly.

Have a nice day :)

[clemstoquart]

Fix by https://github.com/gradle/playframework/pull/98