chore(deps): update pnpm/action-setup action to v6

Author: renovate[bot]

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

@@ -14,7 +14,7 @@ jobs:
         node-version: [20.x]
     steps:
       - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@v3
+      - uses: pnpm/action-setup@v6
         with:
           version: 8
       - name: Setting up Node.js ${{ matrix.node-version }}