SOLR-6578: Update commons-io dependency to the latest 2.4 version

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1633718 13f79535-47bb-0310-9956-ffa450edef68
SOLR-6578: added CHANGES.txt entry

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1633721 13f79535-47bb-0310-9956-ffa450edef68