How to have automatic update of gradle dependencies by using a defined file for dependencies?

Hi,

In my project, I have a dependencies.gradle file. In this one, I have differents arrays of dependencies with corresponding version.

I would like to know if is there a way to have automatic update available version for dependency with this way ?

For example, if i declare com.android.support:appcompat-v7:27.0.2 in build.gradle directly, it'll tell me that a new version is available. Actually, it's declared in my dependencies.gradle like this :

appCompat : "com.android.support:appcompat-v7:$appCompatVersion"

and the version is in the same file, define above like this : appCompatVersion = "27.0.2"

Android Studio doesn't tell me that a new version is available. I'm looking on internet but didn't find anything. Does any one know how I can proceed to achieve this ?