Provide Gradle builder for Gradle v5.0 (and possibly Gradle v4.10.3)

[dubinsky]

Latest Gradle version supported by the builder is v4.6.
Projects that use latest versions of certain plugins (e.g., com.bmuschko.docker-remote-api) or more current Gradle features (e.g., publishing) require later versions of Gradle.

[Strat1987]

would also appreciate bumping the version for this builder. Also at this time it seems it uses the 4.0 as a default. Can you please also update the readme on how to use explicit version?