chore(deps): update pnpm to v9

Author: renovate[bot]

package.json

@@ -23,7 +23,7 @@
   },
   "volta": {
     "node": "20.15.1",
-    "pnpm": "8.8.0"
+    "pnpm": "9.7.1"
   },
   "changelog": {
     "repo": "mainmatter/qunit-dom",

packages/qunit-dom/package.json

@@ -67,7 +67,7 @@
   "dependencies": {
     "dom-element-descriptors": "^0.5.1"
   },
-  "packageManager": "pnpm@8.8.0",
+  "packageManager": "pnpm@9.7.1",
   "volta": {
     "extends": "../../package.json"
   }