Update pnpm to v8.15.1

Author: renovate[bot]

package.json

@@ -35,7 +35,7 @@
     "prettier-plugin-ember-template-tag": "^2.0.0",
     "turbo": "^1.12.2"
   },
-  "packageManager": "pnpm@8.14.3",
+  "packageManager": "pnpm@8.15.1",
   "pnpm": {
     "overrides": {
       "@nullvoxpopuli/eslint-configs": "^3.2.2",