ci: add missing pnpm setup

Author: Meierschlumpf

.github/workflows/release.yaml

@@ -23,6 +23,7 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ steps.obtainToken.outputs.token }}
         uses: actions/checkout@v5
+      - uses: pnpm/action-setup@v4
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v4
         with: