chore(deps): bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Commits](actions/checkout@v4...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/ci.yml

@@ -95,7 +95,7 @@ jobs:
     name: ${{ matrix.os }} ${{ matrix.cxx || 'MSVC' }}${{ matrix.name_suffix || '' }}
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Setup Ninja (Ubuntu)
         if: startsWith(matrix.os, 'ubuntu')
@@ -152,7 +152,7 @@ jobs:
     name: Rust ${{ matrix.toolchain }} / ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@master

.github/workflows/commitlint.yml

@@ -21,7 +21,7 @@ jobs:
         env:
           EVENT: ${{ toJSON(github.event) }}
       - name: Checkout
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8  # v6.0.1
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4.3.1
         with:
           persist-credentials: false
           sparse-checkout: .

.github/workflows/release.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8  # v6.0.1
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4.3.1
         with:
           persist-credentials: false
 
@@ -64,7 +64,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@master