chore(deps): update dependency com.google.cloud:cloud-spanner-spring-data-r2dbc to v0.6.0 (GoogleCloudPlatform#5664)

Author: renovate-bot

spanner/r2dbc/pom.xml

@@ -30,7 +30,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>cloud-spanner-spring-data-r2dbc</artifactId>
-      <version>0.5.0</version>
+      <version>0.6.0</version>
     </dependency>
     <!-- [END spanner_spring_data_r2dbc_dependency] -->