deps: update dependency com.google.cloud:google-cloud-spanner to v6.99.0 (#2192)

Author: renovate-bot

samples/spring-data-mybatis/googlesql/pom.xml

@@ -94,7 +94,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-spanner</artifactId>
-      <version>6.98.1</version>
+      <version>6.99.0</version>
       <type>test-jar</type>
       <scope>test</scope>
     </dependency>