fix(plugin-legacy): require Vite 2.8.0 (#6272) (#6869)

Author: agriffis

packages/plugin-legacy/package.json

@@ -33,6 +33,6 @@
     "systemjs": "^6.12.1"
   },
   "peerDependencies": {
-    "vite": "^2.7.8"
+    "vite": "^2.8.0"
   }
 }