Update smoke test on PR to use pnpm

.github/workflows/pr-smoke-test.yml

@@ -1,6 +1,8 @@
 name: Run smoke tests against pull request.
 on:
   pull_request:
+    branches:
+      - trunk
     types:
       - labeled
 jobs:
@@ -19,14 +21,16 @@ jobs:
       - name: Checkout code.
         uses: actions/checkout@v2
         with:
-          ref: trunk
+          path: package/woocommerce
 
       - name: Install prerequisites.
+        working-directory: package/woocommerce/plugins/woocommerce
         run: |
-          npm install
+          npm install -g pnpm
+          pnpm install
           composer install --no-dev
-          npm run build:assets
-          npm install jest
+          pnpm run build:assets
+          pnpm install jest
           
       - name: Run smoke test.
         env:
@@ -43,8 +47,8 @@ jobs:
           UPDATE_WC: 1
           DEFAULT_TIMEOUT_OVERRIDE: 120000
         run: |
-          npx wc-e2e test:e2e ./tests/e2e/specs/smoke-tests/update-woocommerce.js
-          npx wc-e2e test:e2e
+          pnpx wc-e2e test:e2e plugins/woocommerce/tests/e2e/specs/smoke-tests/update-woocommerce.js
+          pnpx wc-e2e test:e2e
 
       - name: Remove label from pull request.
         if: "${{ contains(github.event.pull_request.labels.*.name, 'run: smoke tests') }}"