Remove deprecation stacktrace on Gradle 3.2

[szpak]

<< has been deprecated in Gradle 3.x and a nasty stack trace is print in the projects using this plugin.

The Task.leftShift(Closure) method has been deprecated and is scheduled to be removed in Gradle 5.0. Please use Task.doLast(Action) instead.
        at org.gradle.api.internal.AbstractTask.leftShift(AbstractTask.java:505)
        at org.gradle.api.Task$leftShift.call(Unknown Source)
        at com.ofg.uptodate.UptodatePlugin.apply(UptodatePlugin.groovy:36)
        at com.ofg.uptodate.UptodatePlugin.apply(UptodatePlugin.groovy)
        at org.gradle.api.internal.plugins.ImperativeOnlyPluginApplicator.applyImperative(ImperativeOnlyPluginApplicator.java:35)
(...)

Offensive line.

[szpak]

Fixed in master. Waiting for a release.