Update pnpm/action-setup action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
       - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python }}
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
         with:
           version: latest
       - uses: actions/setup-node@v6

.github/workflows/publish_release.yml

@@ -22,7 +22,7 @@ jobs:
       id-token: write
     steps:
       - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
         with:
           version: latest
       - uses: actions/setup-node@v6