Update actions/checkout action to v6 (#626)

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Run Coditsu
@@ -43,7 +43,7 @@ jobs:
           - ruby: '3.4'
             coverage: 'true'
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install package dependencies
         run: "[ -e $APT_DEPS ] || sudo apt-get install -y --no-install-recommends $APT_DEPS"
       - name: Set up Ruby
@@ -75,7 +75,7 @@ jobs:
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Run Coditsu
@@ -102,7 +102,7 @@ jobs:
           - ruby: '3.4'
             coverage: 'true'
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install package dependencies
         run: "[ -e $APT_DEPS ] || sudo apt-get install -y --no-install-recommends $APT_DEPS"
       - name: Set up Ruby