Fix source version for bulk_transfer example

Author: manuelbl

examples/bulk_transfer/pom.xml

@@ -13,8 +13,8 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.source>19</maven.compiler.source>
-    <maven.compiler.target>19</maven.compiler.target>
+    <maven.compiler.source>20</maven.compiler.source>
+    <maven.compiler.target>20</maven.compiler.target>
   </properties>
 
   <dependencies>