chore(deps): update dependency com.google.cloud:libraries-bom to v16.4.0 (#506)

Author: renovate-bot

java-pubsub/samples/snippets/pom.xml

@@ -45,7 +45,7 @@
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>libraries-bom</artifactId>
-        <version>16.3.0</version>
+        <version>16.4.0</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>