Upgrade Java 11 CI image to openjdk:11.ea-28-jdk

[gandrade]

According to https://hub.docker.com/_/openjdk/, update the current Java 11 CI version to the latest one. available (openjdk:11.ea-28-jdk)

[snicoll]

Closing in favour of PR #14631

@gandrade fyi we don't need an issue if you intend to submit a PR. A PR only is enough.

[gandrade]

@snicoll Got it. Thanks for the heads-up. 👍