chore(samples): Add samples for Cloud Spanner Default Backup Schedules.

Adding `s` to create instance sample class name

Author: Sally-Ye

samples/install-without-bom/pom.xml

@@ -33,7 +33,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-spanner</artifactId>
-      <version>6.79.0</version>
+      <version>6.80.0</version>
     </dependency>
     <!-- [END spanner_install_without_bom] -->