set Checkout Pull Request step (#9)

* set `Checkout Pull Request step`

ref: actions/checkout#331 (comment)

* fix condition

* fix

Author: tnyo43

.github/workflows/test-action.yml

@@ -13,17 +13,21 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       pull-requests: write
-    if: github.event.issue.pull_request
+    if: github.event_name != 'issue_comment' || github.event.issue.pull_request
     steps:
-      - name: Get PR branch
-        uses: xt0rted/pull-request-comment-branch@v1
-        id: comment-branch
-
       - name: Checkout
         id: checkout
         uses: actions/checkout@v4
-        with:
-          ref: ${{ steps.comment-branch.outputs.head_ref }}
+
+      - name: Checkout Pull Request
+        if: github.event.issue.pull_request
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          PR_URL="${{ github.event.issue.pull_request.url }}"
+          PR_NUM=${PR_URL##*/}
+          echo "Checking out from PR #$PR_NUM based on URL: $PR_URL"
+          hub pr checkout $PR_NUM
 
       - name: Test Local Action
         id: test-action