chore(deps): update dependency com.google.cloud:cloud-spanner-r2dbc to v0.6.0 (GoogleCloudPlatform#5663)

Author: renovate-bot

spanner/r2dbc/pom.xml

@@ -41,7 +41,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>cloud-spanner-r2dbc</artifactId>
-      <version>0.5.0</version>
+      <version>0.6.0</version>
     </dependency>
     <!-- [END spanner_r2dbc_dependency] -->