Remove name specification for instance (#347)

* Remove name specification for instance

* Close environment as well

packages/db/src/engines/LmDb.ts

@@ -33,12 +33,12 @@ export default class LmDb implements BaseDb {
   close (): void {
     this._dbi.close();
     this._dbi = null;
+    this._env.close();
   }
 
   open (): void {
     this._dbi = this._env.openDbi({
       create: true,
-      name: 'lmdb',
       keyIsBuffer: true
     });
   }