build(deps): bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/actionlint.yml

@@ -15,7 +15,7 @@ jobs:
   actionlint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - 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/docs.yml

@@ -17,7 +17,7 @@ jobs:
         poetry-version: ["1.8.5"]
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: "Install Poetry ${{matrix.poetry-version}}"
         run: pipx install poetry==${{matrix.poetry-version}}
       - name: "Setup Python ${{matrix.python-version}}"

.github/workflows/python-check.yml

@@ -21,7 +21,7 @@ jobs:
         poetry-version: ["1.8.5"]
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: "Install Poetry ${{matrix.poetry-version}}"
         run: pipx install poetry==${{matrix.poetry-version}}
       - name: "Setup Python ${{matrix.python-version}}"
@@ -50,7 +50,7 @@ jobs:
         os: ["ubuntu-latest", "windows-latest", "macos-latest"]
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: "Install Poetry ${{matrix.poetry-version}}"
         run: pipx install poetry==${{matrix.poetry-version}}
       - name: "Setup Python ${{matrix.python-version}}"

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
         poetry-version: ["1.8.5"]
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: "Install Poetry ${{matrix.poetry-version}}"
         run: pipx install poetry==${{matrix.poetry-version}}
       - name: "Setup Python"