[Java] Document JSON-B as microprofile client target

Created by: languitar

The documentation for the Java microprofile client wrongly states that Jackson is used. This commit corrects this to JSON-B.

Relates to: #8015

CC @bbdouglas @sreeshas @jfiala @lukoyanov @cbornet @jeff9finger @karismann @Zomzog @lwlee2608 @nmuesch

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