variant.getGenerateBuildConfig()' is obsolete

[felixeduardo15]

INFO: API 'variant.getGenerateBuildConfig()' is obsolete and has been replaced with 'variant.getGenerateBuildConfigProvider()'.
It will be removed at the end of 2019.
For more information, see https://d.android.com/r/tools/task-configuration-avoidance.
To determine what is calling variant.getGenerateBuildConfig(), use -Pandroid.debug.obsoleteApi=true on the command line to display more information.
Affected Modules: app