reflect 42.2.4 release in readme.md [ci-skip]
reflect 42.2.4 release in readme.md
[ci-skip]

golovnin/pgjdbc,sehrope/pgjdbc,pgjdbc/pgjdbc,AlexElin/pgjdbc,jorsol/pgjdbc,AlexElin/pgjdbc,marschall/pgjdbc,marschall/pgjdbc,davecramer/pgjdbc,davecramer/pgjdbc,golovnin/pgjdbc,sehrope/pgjdbc,golovnin/pgjdbc,sehrope/pgjdbc,pgjdbc/pgjdbc,marschall/pgjdbc,jorsol/pgjdbc,sehrope/pgjdbc,AlexElin/pgjdbc,marschall/pgjdbc,jorsol/pgjdbc,davecramer/pgjdbc,pgjdbc/pgjdbc,pgjdbc/pgjdbc,davecramer/pgjdbc,jorsol/pgjdbc