deps: update dependency com.google.cloud:google-cloud-spanner-bom to v6.81.2 (googleapis#1837)

Author: renovate-bot

samples/spring-data-jdbc/pom.xml

@@ -30,7 +30,7 @@
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-spanner-bom</artifactId>
-        <version>6.81.1</version>
+        <version>6.81.2</version>
         <scope>import</scope>
         <type>pom</type>
       </dependency>