chore(dependencies): make medusa-interfaces a peerDependency

packages/medusa-fulfillment-manual/package.json

@@ -27,6 +27,9 @@
     "prepare": "cross-env NODE_ENV=production npm run build",
     "watch": "babel -w src --out-dir . --ignore **/__tests__"
   },
+  "peerDependencies": {
+    "medusa-interfaces": "1.x"
+  },
   "dependencies": {
     "@babel/plugin-transform-classes": "^7.9.5",
     "@babel/plugin-transform-instanceof": "^7.8.3",