Update Log4j to 2.17.2

This fixes the Slack appender. It couldn't be cherry-picked from the
development branch because Log4j version is managed in the
pavlab-starter-parent package.

Author: arteymix

pom.xml

@@ -670,7 +670,7 @@
 		<tomcat.version>8.5.72</tomcat.version>
 		<mysql.version>8.0.28</mysql.version>
 		<lucene.version>3.6.2</lucene.version>
-		<log4j2.version>2.17.1</log4j2.version>
+		<log4j2.version>2.17.2</log4j2.version>
 		<slf4j.version>1.7.32</slf4j.version>
 		<slack.version>1.18.0</slack.version>
 	</properties>