chore(deps): update pnpm to v8 (#40)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -1,7 +1,7 @@
 {
   "name": "unplugin-vue2",
   "version": "0.1.1",
-  "packageManager": "pnpm@7.33.3",
+  "packageManager": "pnpm@8.6.7",
   "author": "Ray <[email protected]> (@so1ve)",
   "description": "Unplugin for Vue 2.7+.",
   "keywords": [