The quarkus kubernetes extension no longer defaults to the fabric8-s2i base image. It chooses ubi9/openjdk-17 if the local java version is 17 and 21 for 21.

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This removes a stale reference to `fabric8/s2i-java` which was misleading and provides two example default values that correspond to the current plugin defaults. The chosen value is affected by the local system's JDK version.

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