Bump to GitBucket 4.24.0

Author: takezoe

build.sbt

@@ -1,8 +1,8 @@
 organization := "io.github.gitbucket"
 name := "gitbucket-gist-plugin"
 version := "4.14.0"
-scalaVersion := "2.12.4"
-gitbucketVersion := "4.23.1"
+scalaVersion := "2.12.6"
+gitbucketVersion := "4.24.0"
 
 scalacOptions := Seq("-deprecation", "-feature", "-language:postfixOps")
 javacOptions in compile ++= Seq("-target", "8", "-source", "8")