upgrade jackson to 2.9.8

Author: stevehu

pom.xml

@@ -56,7 +56,7 @@
         <version.light-rest-4j>1.5.26</version.light-rest-4j>
         <version.openapi-parser>1.5.26</version.openapi-parser>
         <version.json-schema-validator>0.1.26</version.json-schema-validator>
-        <version.jackson>2.9.5</version.jackson>
+        <version.jackson>2.9.8</version.jackson>
         <version.slf4j>1.7.25</version.slf4j>
         <version.jose4j>0.6.3</version.jose4j>
         <version.antlr4>4.7</version.antlr4>