deps: update dependency com.google.cloud:google-cloud-pubsub-bom to v1.108.0 (#157)

Author: renovate-bot

pom.xml

@@ -25,7 +25,7 @@
  <dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-pubsub-bom</artifactId>
- <version>1.107.0</version>
+ <version>1.108.0</version>
  <type>pom</type>
  <scope>import</scope>
  </dependency>