Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/actionlint.yml

@@ -15,7 +15,7 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Download actionlint
         id: get_actionlint
         run: bash <(curl https://raw.githubusercontent.com/rhysd/actionlint/main/scripts/download-actionlint.bash)

.github/workflows/copyrights.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: yegor256/copyrights-action@0.0.12

.github/workflows/lean.yml

@@ -26,7 +26,7 @@ jobs:
           echo "$HOME/.elan/bin" >> $GITHUB_PATH
 
       - name: '📥 Checkout repository'
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: '👝 Cache .lake/'
         id: cache-lake

.github/workflows/markdown-lint.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: DavidAnson/markdownlint-cli2-action@v20.0.0

.github/workflows/pdd.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: volodya-lombrozo/pdd-action@master

.github/workflows/reuse.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: fsfe/reuse-action@v5

.github/workflows/typos.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: crate-ci/typos@v1.35.1

.github/workflows/xcop.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: g4s8/xcop-action@master

.github/workflows/yamllint.yml

@@ -15,5 +15,5 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ibiqlik/action-yamllint@v3