chore(deps): update dependency com.google.cloud:google-cloud-pubsublite to v1.15.6 (googleapis#1827)

Author: renovate-bot

samples/snippets/pom.xml

@@ -46,7 +46,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-pubsublite</artifactId>
-      <version>1.15.3</version>
+      <version>1.15.6</version>
     </dependency>
     <dependency>
       <groupId>com.google.cloud</groupId>