Bump actions/checkout from 5 to 6 (#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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/codeql-qlt-unit-tests.yml

@@ -24,7 +24,7 @@ jobs:
       has_languages: ${{ steps.find-languages.outputs.has_languages }}
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup CodeQL environment for discovering unit tests
         uses: ./.github/actions/setup-codeql-environment
@@ -96,7 +96,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup CodeQL environment for executing `qlt` unit tests
         uses: ./.github/actions/setup-codeql-environment
@@ -161,7 +161,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup CodeQL environment for validating `qlt` unit tests
         uses: ./.github/actions/setup-codeql-environment

.github/workflows/copilot-setup-steps.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Copilot Setup - Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Copilot Setup - Setup CodeQL environment
         uses: ./.github/actions/setup-codeql-environment

.github/workflows/lint-and-format.yml

@@ -35,7 +35,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6