update json4s from version 3.4.0 to 3.4.2; release json-auto-convert:0.3 based on json4s:3.4.2
update json4s from version 3.4.0 to 3.4.2; release json-auto-convert:0.3 based on json4s:3.4.2

ubirch/ubirch-scala-utils