fix sdk-platform-java-config relativePath

Author: chingor13

google-cloud-pom-parent/pom.xml

@@ -16,7 +16,7 @@
     <groupId>com.google.cloud</groupId>
     <artifactId>sdk-platform-java-config</artifactId>
     <version>3.57.1-SNAPSHOT</version><!-- {x-version-update:google-cloud-shared-dependencies:current} -->
-    <relativePath/>
+    <relativePath>../sdk-platform-java/sdk-platform-java-config</relativePath>
   </parent>
 
   <properties>