chore: upgrade pnpm action in CI workflow

- Updated pnpm/action-setup from version 4 to 6 in the GitHub Actions workflow.

Author: ogroppo

.github/workflows/npm-publish.yml

@@ -15,9 +15,7 @@ jobs:
         with:
           fetch-depth: 0
       - name: install pnpm
-        uses: pnpm/action-setup@v4
-        with:
-          version: 9.4.0
+        uses: pnpm/action-setup@v6
       - name: setup node.js
         uses: actions/setup-node@v6
         with: