fix: use global scope for metadata storage (#929)

Author: petrzjunior

src/storage.ts

@@ -1,6 +1,13 @@
 import { MetadataStorage } from './MetadataStorage';
+import { getGlobal } from './utils';
+
+const globalScope = getGlobal();
 
 /**
  * Default metadata storage is used as singleton and can be used to storage all metadatas.
  */
-export const defaultMetadataStorage = new MetadataStorage();
+if (!globalScope.classTransformerMetadataStorage) {
+  globalScope.classTransformerMetadataStorage = new MetadataStorage();
+}
+
+export const defaultMetadataStorage = globalScope.classTransformerMetadataStorage;