chore: use pnpmm action instead of global install

Author: MehulKChaudhari

.github/workflows/gh-pages.yml

@@ -15,8 +15,12 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: '20'
-      - run: npm install -g pnpm@9
-      - run: pnpm install
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          cache: 'pnpm'
+          node-version: 20
+      - run: pnpm i --frozen-lockfile
       - run: npx lint-to-the-future output -o lttfOutput --rootUrl ember-api-docs --previous-results https://ember-learn.github.io/ember-api-docs/data.json
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v3