chore(helm): update pipeline-backend db version (#487)

Because

- The pipeline-backend db version has been updated.

This commit

- Updates pipeline-backend db version.

charts/core/values.yaml

@@ -406,7 +406,7 @@ pipelineBackend:
   # -- The path of configuration file for pipeline-backend
   configPath: /pipeline-backend/config/config.yaml
   # -- The database migration version
-  dbVersion: 12
+  dbVersion: 13
   # -- workflow setting
   workflow:
     maxWorkflowTimeout: 3600 # in seconds