chore: fix snapshot repo url (GoogleCloudPlatform#349)

* chore: fix snapshot repo url

* chore: fix snapshot repo url

Author: akerekes

function-maven-plugin/pom.xml

@@ -168,6 +168,7 @@
             <extensions>true</extensions>
             <configuration>
               <publishingServerId>sonatype-central-portal</publishingServerId>
+              <centralSnapshotsUrl>https://central.sonatype.com/repository/maven-snapshots/</centralSnapshotsUrl>
             </configuration>
           </plugin>
         </plugins>