fix: add @types/node as an optional peer dependency (#10757)

The built bundle of Vite starts with a reference to `node` types:
https://unpkg.com/browse/vite@3.2.2/dist/node/index.d.ts

This means those who depend on Vite type definitions should install
`@types/node` in their projects to successfully do type-checking.
In that sense, `@types/node` is an optional peer dependency of Vite.

After this being fixed, we should revert vitejs/vite-ecosystem-ci#85 because not explicitly depending on
`@types/node` *should* be erroneous. The ecosystem CI shouldn't cover
that error for downstream packages.

packages/vite/package.json

@@ -123,13 +123,17 @@
     "ws": "^8.10.0"
   },
   "peerDependencies": {
+    "@types/node": ">= 14",
     "less": "*",
     "sass": "*",
     "stylus": "*",
     "sugarss": "*",
     "terser": "^5.4.0"
   },
   "peerDependenciesMeta": {
+    "@types/node": {
+      "optional": true
+    },
     "sass": {
       "optional": true
     },