functions: shrink Kotlin example POM (GoogleCloudPlatform#2846)

* functions: shrink Kotlin example POM

@saturnism FYI

* Update pom.xml

Move region tags

* Update pom.xml

Author: Ace Nassri

functions/helloworld/kotlin-helloworld/pom.xml

@@ -165,7 +165,6 @@
             <configuration>
               <sourceDirs>
                 <source>src/main/kotlin</source>
-                <source>target/generated-sources/annotations</source>
               </sourceDirs>
             </configuration>
           </execution>