PDFBOX-5660: update log4j

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1916227 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 2940885..4e9b059 100644
--- a/pom.xml
+++ b/pom.xml
@@ -56,7 +56,7 @@
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 
     <bouncycastle.version>1.77</bouncycastle.version>
-    <log4j2.version>2.23.0</log4j2.version>
+    <log4j2.version>2.23.1</log4j2.version>
     <junit.version>5.10.2</junit.version>
     <jbig2.version>3.0.4</jbig2.version>
     <jai.version>1.4.0</jai.version>