Ensure playgrounds work + switch to npm workspaces (#2907)

* bump Next in playground

* convert legacy Link after Next.js bump

* update yarn.lock

* switch to npm workspaces

* move `packages/playground-*` to `playgrounds/*`

* use `npm` instead of `yarn`

* sync package-lock.json

* use node 20 for insiders releases

package.json

@@ -7,21 +7,22 @@
   "license": "MIT",
   "private": true,
   "workspaces": [
-    "packages/*"
+    "packages/*",
+    "playgrounds/*"
   ],
   "scripts": {
-    "react": "yarn workspace @headlessui/react",
-    "react-playground": "yarn workspace playground-react dev",
-    "playground-react": "yarn workspace playground-react dev",
-    "vue": "yarn workspace @headlessui/vue",
-    "playground-vue": "yarn workspace playground-vue dev",
-    "vue-playground": "yarn workspace playground-vue dev",
-    "clean": "yarn workspaces run clean",
+    "react": "npm run --workspace=@headlessui/react",
+    "react-playground": "npm run --workspace=playground-react dev",
+    "playground-react": "npm run --workspace=playground-react dev",
+    "vue": "npm run --workspace=@headlessui/vue",
+    "playground-vue": "npm run --workspace=playground-vue dev",
+    "vue-playground": "npm run --workspace=playground-vue dev",
+    "clean": "npm run clean --workspaces --if-present",
     "build": "npm-run-all -p 'react build' 'vue build'",
     "test": "./scripts/test.sh",
     "lint": "./scripts/lint.sh",
     "lint-check": "CI=true ./scripts/lint.sh",
-    "lint-types": "CI=true yarn workspaces run lint-types",
+    "lint-types": "CI=true npm run lint-types --workspaces --if-present",
     "release-channel": "node ./scripts/release-channel.js",
     "release-notes": "node ./scripts/release-notes.js",
     "package-path": "node ./scripts/package-path.js"
@@ -32,7 +33,7 @@
     }
   },
   "lint-staged": {
-    "*": "yarn lint"
+    "*": "npm run lint"
   },
   "prettier": {
     "printWidth": 100,