Upgraded Log4J to 2.16.0 to address new vulnerability.

Author: John MacAuley

pom.xml

@@ -147,13 +147,13 @@
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-api</artifactId>
-      <version>[2.15.0,)</version>
+      <version>[2.16.0,)</version>
     </dependency>
 
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-core</artifactId>
-      <version>[2.15.0,)</version>
+      <version>[2.16.0,)</version>
     </dependency>
 
     <!-- Google JSON parsers for reading configuration data from files. -->