update log4j2 to latest, now 2.16.0
diff --git a/pom.xml b/pom.xml
index b85c035..58bf069 100644
--- a/pom.xml
+++ b/pom.xml
@@ -515,7 +515,7 @@
         <jaxbri.version>2.3.5</jaxbri.version>
         <jetty.version>9.4.43.v20210629</jetty.version>
         <jibx.version>1.3.3</jibx.version>
-        <log4j2.version>2.15.0</log4j2.version>
+        <log4j2.version>2.16.0</log4j2.version>
         <maven.archiver.version>3.5.1</maven.archiver.version>
         <maven.version>3.8.2</maven.version>
         <plexus.utils.version>3.4.1</plexus.utils.version>