minor: add 8.20 release notes
minor: add 8.20 release notes

checkstyle/checkstyle,romani/checkstyle,romani/checkstyle,checkstyle/checkstyle,romani/checkstyle,rnveach/checkstyle,rnveach/checkstyle,romani/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,romani/checkstyle,romani/checkstyle,rnveach/checkstyle,checkstyle/checkstyle