update readme for app gradle in android examples

[yptheangel]

update deprecated "compile" to "implementation" notation to import dependencies in app gradle

Signed-off-by: yptheangel [email protected]

[saudet]

I'm sorry, I was forgetting that what we need to update is actually the templates here: https://github.com/eclipse/deeplearning4j/blob/master/docs/deeplearning4j/templates/ Then the docs here should be updated from the output of the scripts, but this hasn't been done in a while, so don't worry about it.