deps: update dependency com.google.guava:guava-testlib to v33.4.8-jre

Author: renovate-bot

google-cloud-datastore/pom.xml

@@ -163,7 +163,7 @@
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava-testlib</artifactId>
-      <version>33.4.0-jre</version>
+      <version>33.4.8-jre</version>
       <scope>test</scope>
     </dependency>
     <!-- Need testing utility classes for generated gRPC clients tests -->