chore(deps): update actions/checkout action to v6 (#158)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/lint-and-build.yml

@@ -10,7 +10,7 @@ jobs:
   lint-and-build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v4
         with:
           cache: npm

.github/workflows/merge-release.yml

@@ -40,7 +40,7 @@ jobs:
           echo 'BRANCH='${{ inputs.branch || 'main' }} >> $GITHUB_ENV
 
       - name: Checkout "${{ env.BRANCH }}" branch locally
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ env.BRANCH }}
           fetch-tags: true

.github/workflows/sync-branches.yml

@@ -24,7 +24,7 @@ jobs:
           app-id: ${{ vars.GHA_APP_ID }}
           private-key: ${{ secrets.GHA_PRIVATE_KEY }}
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           ref: main
           fetch-depth: 0