PDFBOX-5660: update apache parent

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1934079 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

parent/pom.xml

@@ -23,7 +23,7 @@
   <parent>
     <groupId>org.apache</groupId>
     <artifactId>apache</artifactId>
-    <version>37</version>
+    <version>38</version>
     <relativePath />
   </parent>