chore(deps): pin dependency pnpm to 8.15.9

Author: renovate[bot]

.github/workflows/build-and-test.yml

@@ -24,7 +24,7 @@ jobs:
       # https://pnpm.io/continuous-integration#github-actions
       - uses: pnpm/action-setup@v2
         with:
-          version: 8
+          version: 8.15.9
       - name: 🐢 Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v3
         with: