fix: add npm namespace

Author: iowillhoit

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "plugin-data-setup-transfer",
+  "name": "@salesforce/plugin-data-setup-transfer",
   "description": "Transfer setup data from one org to another in a single step",
   "version": "1.0.1",
   "dependencies": {

src/commands/data/setup/transfer.ts

@@ -21,7 +21,7 @@ import { SfCommand, Flags } from '@salesforce/sf-plugins-core';
 import { Messages, Connection, Org } from '@salesforce/core';
 
 Messages.importMessagesDirectoryFromMetaUrl(import.meta.url);
-const messages = Messages.loadMessages('plugin-data-setup-transfer', 'data.setup.transfer');
+const messages = Messages.loadMessages('@salesforce/plugin-data-setup-transfer', 'data.setup.transfer');
 
 type DefinitionForeignKey = {
   field: string;