test(deps): update dependency org.mockito:mockito-core to v4.8.0

Author: renovate-bot

google-cloud-spanner/pom.xml

@@ -338,7 +338,7 @@
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-core</artifactId>
-      <version>4.7.0</version>
+      <version>4.8.0</version>
       <scope>test</scope>
     </dependency>
     <dependency>