Update actions/checkout action to v6 (#243)

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

Author: renovate[bot]

.github/workflows/build.yml

@@ -7,7 +7,7 @@ jobs:
   build:
     runs-on: ubuntu-24.04
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set Node.js 20.x
       uses: actions/setup-node@v6
       with:
@@ -31,7 +31,7 @@ jobs:
     name: "Build and release action"
     needs: [build]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
           persist-credentials: true

.github/workflows/example.yml

@@ -9,7 +9,7 @@ jobs:
   hello:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ./
         id: check
         with:
@@ -20,7 +20,7 @@ jobs:
   eyes:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ./
         id: check
         with:
@@ -34,7 +34,7 @@ jobs:
   rocket:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ./
         id: check
         with: