Update mainargs from 0.6.2 to 0.6.3 (#3114)

Pull request: #3114

Author: lefou

build.sc

@@ -152,7 +152,7 @@ object Deps {
   val log4j2Core = ivy"org.apache.logging.log4j:log4j-core:2.23.0"
   val osLib = ivy"com.lihaoyi::os-lib:0.9.3"
   val pprint = ivy"com.lihaoyi::pprint:0.8.1"
-  val mainargs = ivy"com.lihaoyi::mainargs:0.6.2"
+  val mainargs = ivy"com.lihaoyi::mainargs:0.6.3"
   val millModuledefsVersion = "0.10.9"
   val millModuledefsString = s"com.lihaoyi::mill-moduledefs:${millModuledefsVersion}"
   val millModuledefs = ivy"${millModuledefsString}"