build.gradle: replace deprecated API
build.gradle: replace deprecated API

ConfigurableReport#setDestination(Object) is deprecated. [1]

Let's replace this with ConfigurableReport#setDestination(File).

[1]: https://docs.gradle.org/current/javadoc/org/gradle/api/reporting/ConfigurableReport.html#setDestination-java.lang.Object-

se-edu/addressbook-level3