PDFBOX-5660: add comment

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1926855 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

parent/pom.xml

@@ -57,6 +57,7 @@
 
     <bouncycastle.version>1.81</bouncycastle.version>
     <log4j2.version>2.25.0</log4j2.version>
+    <!-- can't update to 6.0.0, needs jdk17 -->
     <junit.version>5.13.2</junit.version>
     <jbig2.version>3.0.4</jbig2.version>
     <jai.version>1.4.0</jai.version>