Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/build-check.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
       # 1. 레포지토리 체크아웃
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # 2. Pnpm 설정
       - name: Setup Pnpm

.github/workflows/deploy.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Deploy to Vercel
         uses: mountainash/deploy-to-vercel-action@v2.5.0

.github/workflows/playwright.yml

@@ -9,7 +9,7 @@ jobs:
     timeout-minutes: 60
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: actions/setup-node@v4
       with:
         node-version: lts/*

.github/workflows/storybook.yml

@@ -22,7 +22,7 @@ jobs:
       status: ${{ job.status }}
     steps:
       - name: checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0