chore(docs): update first-party-dependencies link (#6490)

Author: GarreltMock

libraries-bom/pom.xml

@@ -59,8 +59,8 @@
 
   <dependencyManagement>
     <dependencies>
-      <!-- first-party-dependencies is part of google-cloud-shared-dependencies
-           BOM in https://github.com/googleapis/java-shared-dependencies/blob/main/first-party-dependencies/pom.xml.
+      <!-- first-party-dependencies is part of java-shared-dependencies
+           BOM in https://github.com/googleapis/sdk-platform-java/blob/main/java-shared-dependencies/first-party-dependencies/pom.xml.
            This includes Guava, Protobuf, gRPC, Google Auth Libraries, etc. -->
       <dependency>
         <groupId>com.google.cloud</groupId>