fix: migration bug of plugin config

pkg/persistence/migrations/dbm008_plugin_config.py

@@ -0,0 +1,20 @@
+from .. import migration
+
+
+@migration.migration_class(8)
+class DBMigratePluginConfig(migration.DBMigration):
+    """插件配置"""
+
+    async def upgrade(self):
+        """升级"""
+
+        if 'plugin' not in self.ap.instance_config.data:
+            self.ap.instance_config.data['plugin'] = {
+                'runtime_ws_url': 'ws://localhost:5400/control/ws',
+            }
+
+            await self.ap.instance_config.dump_config()
+
+    async def downgrade(self):
+        """降级"""
+        pass