Case 1 (Templating Solution): Many dependencies from one project used

build.gradle

dependencies {
  implementation deps.retrofit
  implementation deps.retrofitGson 
}

root-build.gradle

buildscript {
  ext.versions = [
    retrofitVersion: "2.3.0"
  ]

  ext.deps = [
    retrofit: "com.squareup.retrofit2:retrofit:$versions.retrofitVersion", 
    retrofitGson: "com.squareup.retrofit2:converter-gson:$versions.retrofitVersion"
  ]
}