chore(deps): update actions/checkout action to v6 (#369)

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

Author: renovate[bot]

.github/workflows/continuous-delivery.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Project
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Docker Buildx
         uses: docker/setup-buildx-action@v3.11.1
       - name: Login to GitHub Container Registry

.github/workflows/continuous-integration.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Project
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Add problem matchers
         run: echo "::add-matcher::.github/problemMatchers/eslint.json"
       - name: Use Node.js v8
@@ -31,7 +31,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Project
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Add problem matchers
         run: echo "::add-matcher::.github/problemMatchers/tsc.json"
       - name: Use Node.js v20
@@ -50,7 +50,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Project
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Add problem matchers
         run: echo "::add-matcher::.github/problemMatchers/tsc.json"
       - name: Use Node.js v20

.github/workflows/labelsync.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Project
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           sparse-checkout: .github/labels.yml
           sparse-checkout-cone-mode: false