Merge branch 'log4j2-security-issue' into 'master'

security fix in log4j2 zero day exploit https://www.lunasec.io/docs/blog/log4j-zero-day/

See merge request !51

pom.xml

@@ -36,7 +36,7 @@
 		<hsqldb.version>2.5.0</hsqldb.version>
 		<postgresql-jdbc.version>42.2.5</postgresql-jdbc.version>
 		<jackson.version>2.9.8</jackson.version>
-		<log4j2.version>2.9.0</log4j2.version>
+		<log4j2.version>2.15.0</log4j2.version>
 		<jaxb.version>2.3.0</jaxb.version>
 		<unboundid-ldapsdk.version>4.0.10</unboundid-ldapsdk.version>
 	</properties>
@@ -293,7 +293,7 @@
 		<dependency>
 			<groupId>org.apache.logging.log4j</groupId>
 			<artifactId>log4j-slf4j-impl</artifactId>
-			<version>2.9.0</version>
+			<version>${log4j2.version}</version>
 		</dependency>
 
 		<dependency>