Update jackson-databind 2.7.9.1

to address FasterXML/jackson-databind#1599

With 2.8.10, it degrades the serialization performance of
jackson-dataformat-msgpack down to 62%.

Author: komamitsu

build.sbt

@@ -115,7 +115,7 @@ lazy val msgpackJackson =
         "org.msgpack.jackson.dataformat"
       ),
       libraryDependencies ++= Seq(
-        "com.fasterxml.jackson.core" % "jackson-databind" % "2.7.1",
+        "com.fasterxml.jackson.core" % "jackson-databind" % "2.7.9.1",
         junitInterface,
         "org.apache.commons" % "commons-math3" % "3.6.1" % "test"
       ),