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] <[email protected]>

Author: dependabot[bot]

.github/workflows/build-test.yml

@@ -32,7 +32,7 @@ jobs:
             python: { version: "3.7", toxenv: "py37" }
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: ${{ matrix.python.version }}

.github/workflows/codeql.yml

@@ -46,7 +46,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/publish-to-pypi.yml

@@ -21,7 +21,7 @@ jobs:
       - style_check
       - run_tests
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: "3.10"

.github/workflows/style-check.yml

@@ -11,7 +11,7 @@ jobs:
     name: FString Formatting (flynt)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: "3.10"
@@ -26,7 +26,7 @@ jobs:
     name: Sort Import (isort)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: "3.10"
@@ -41,7 +41,7 @@ jobs:
     name: Code Formatting (black)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: "3.10"
@@ -56,7 +56,7 @@ jobs:
     name: Linting (flake8)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: "3.10"