upgrade undertow to 2.3.15.Final

Author: stevehu

pom.xml

@@ -110,7 +110,7 @@
         <version.junit>5.7.0</version.junit>
         <version.mockito>2.23.0</version.mockito>
         <version.powermock>2.0.0</version.powermock>
-        <version.undertow>2.3.14.Final</version.undertow>
+        <version.undertow>2.3.15.Final</version.undertow>
         <versions.maven-version>2.4</versions.maven-version>
         <version.json-schema-validator>1.5.1</version.json-schema-validator>
         <version.maven-javadoc>3.4.1</version.maven-javadoc>