deps: update dependency com.google.cloud:google-cloud-spanner-jdbc to v2.40.0 (#7493)

Author: renovate-bot

google-cloud-bom/pom.xml

@@ -181,7 +181,7 @@
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-spanner-jdbc</artifactId>
-        <version>2.39.0</version>
+        <version>2.40.0</version>
       </dependency>
       <dependency>
         <groupId>com.google.cloud</groupId>