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)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [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/build.yml

@@ -51,7 +51,7 @@ jobs:
     steps:
       # https://github.com/actions/checkout
       - name: Checkout codebase
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # https://github.com/actions/setup-node
       - name: Install Node.js ${{ matrix.node-version }}
@@ -316,7 +316,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Download artifacts from previous 'tests' job
       - name: Download coverage artifacts

.github/workflows/codescan.yml

@@ -35,7 +35,7 @@ jobs:
     steps:
       # https://github.com/actions/checkout
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Initializes the CodeQL tools for scanning.
       # https://github.com/github/codeql-action

.github/workflows/docker.yml

@@ -77,7 +77,7 @@ jobs:
     steps:
       # Checkout our codebase (to get access to Docker Compose scripts)
       - name: Checkout codebase
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       # Download Docker image artifacts (which were just built by reusable-docker-build.yml)
       - name: Download Docker image artifacts
         uses: actions/download-artifact@v8

.github/workflows/port_merged_pull_request.yml

@@ -23,7 +23,7 @@ jobs:
     if: github.event.pull_request.merged
     steps:
       # Checkout code
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       # Port PR to other branch (ONLY if labeled with "port to")
       # See https://github.com/korthout/backport-action
       - name: Create backport pull requests