chore: restore google-cloud-pubsublite-bom package (#1771)

The google-cloud-pubsublite-bom is used in the libraries-bom: https://github.com/googleapis/java-cloud-bom/blob/2c49bcfe0a415e8255a7c9b3cc94951177a1da92/google-cloud-bom/pom.xml#L234

Author: mpeddada1

pom.xml

@@ -155,6 +155,7 @@
     <module>google-cloud-pubsublite</module>
     <module>grpc-google-cloud-pubsublite-v1</module>
     <module>proto-google-cloud-pubsublite-v1</module>
+    <module>google-cloud-pubsublite-bom</module>
   </modules>
 
   <profiles>