Fix cache path using step outputs instead of env vars

Co-Authored-By: Warp <agent@warp.dev>

Author: erinmikailstaples

.github/workflows/preview-deploy.yml

@@ -34,14 +34,15 @@ jobs:
           version: 9
 
       - name: Get pnpm store directory
+        id: pnpm-cache
         shell: bash
         run: |
-          echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_ENV
+          echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_OUTPUT
 
       - name: Setup pnpm cache
         uses: actions/cache@v4
         with:
-          path: ${{ env.STORE_PATH }}
+          path: ${{ steps.pnpm-cache.outputs.STORE_PATH }}
           key: ${{ runner.os }}-pnpm-store-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
             ${{ runner.os }}-pnpm-store-