docs: remove redundant manual cache due to setup-node cache (#131)

README.md

@@ -1,3 +1,7 @@
+> ## :warning: Upgrade from v2!
+>
+> The v2 version of this action [has stopped working](https://github.com/pnpm/action-setup/issues/135) with newer Node.js versions. Please, upgrade to the latest version to fix any issues.
+
 # Setup pnpm
 
 Install pnpm package manager.
@@ -146,19 +150,6 @@ jobs:
           node-version: 20
           cache: 'pnpm'
 
-      - name: Get pnpm store directory
-        shell: bash
-        run: |
-          echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_ENV
-
-      - uses: actions/cache@v4
-        name: Setup pnpm cache
-        with:
-          path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-${{ hashFiles('**/pnpm-lock.yaml') }}
-          restore-keys: |
-            ${{ runner.os }}-pnpm-store-
-
       - name: Install dependencies
         run: pnpm install
 ```