build(deps): update dependency org.jacoco:jacoco-maven-plugin to v0.8.12 (#2996)

Author: renovate-bot

google-cloud-spanner/pom.xml

@@ -29,7 +29,7 @@
       <plugin>
         <groupId>org.jacoco</groupId>
         <artifactId>jacoco-maven-plugin</artifactId>
-        <version>0.8.11</version>
+        <version>0.8.12</version>
         <executions>
           <execution>
             <goals>