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](https://github.com/actions/checkout/compare/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>

.github/workflows/audit.yaml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Install Rust
         uses: dtolnay/rust-toolchain@v1
         with:

.github/workflows/cd.yaml

@@ -29,7 +29,7 @@ jobs:
             target: aarch64-apple-darwin
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@v1
         with:
@@ -71,7 +71,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@v1
         with:

.github/workflows/changelog.yaml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - uses: dangoslen/changelog-enforcer@v3
         with:

.github/workflows/ci.yaml

@@ -47,7 +47,7 @@ jobs:
             args: --no-deps --document-private-items --all-features --workspace --examples
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Rust toolchain
         uses: dtolnay/rust-toolchain@stable
         with:
@@ -59,7 +59,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Rust toolchain
         uses: dtolnay/rust-toolchain@stable
         with: