ci: update pnpm setup and cache

Author: subframe7536

.github/workflows/publish.yml

@@ -9,11 +9,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10
       - uses: actions/setup-node@v4
         with:
           node-version: 20
-      - run: npm install -g pnpm
-      - run: pnpm install
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
       - name: Publish to Open VSX Registry
         uses: HaaLeo/publish-vscode-extension@v1
         with: