feat: update functions samples

Author: maigovannon

functions/helloworld/helloworld/pom.xml

@@ -50,8 +50,8 @@
   <!-- [START functions_example_pom] -->
   <!-- [START functions_example_pom_dependencies] -->
   <properties>
-    <maven.compiler.target>11</maven.compiler.target>
-    <maven.compiler.source>11</maven.compiler.source>
+    <maven.compiler.target>21</maven.compiler.target>
+    <maven.compiler.source>21</maven.compiler.source>
   </properties>
 
   <dependencies>

functions/v2/pubsub/pom.xml

@@ -31,8 +31,8 @@
   </parent>
 
   <properties>
-    <maven.compiler.target>11</maven.compiler.target>
-    <maven.compiler.source>11</maven.compiler.source>
+    <maven.compiler.target>21</maven.compiler.target>
+    <maven.compiler.source>21</maven.compiler.source>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>