remove gradle deprecation warning

[gernotstarke]

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0.

[gernotstarke]

gradle test --warning-mode all

> Configure project : after processResources config, version= 0.9.8

> Task :compileJava UP-TO-DATE
The following annotation processors were detected on the compile classpath: 
'org.apache.logging.log4j.core.config.plugins.processor.PluginProcessor'. Detecting 
annotation processors on the compile classpath is deprecated and Gradle 5.0 will ignore 
them. Please add them to the annotation processor path instead. If you did not intend to 
use annotation processors, you can use the '-proc:none' compiler argument to ignore them.

BUILD SUCCESSFUL in 3s

[gernotstarke]

fixed by moving log4j into annotationProcesssor group within build.gradle