Bump actions/checkout from 3.6.0 to 4.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.6.0 to 4.0.0.
- [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/v3.6.0...v4.0.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/combine.yml

@@ -6,7 +6,7 @@ jobs:
   combine-prs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3.6.0
+      - uses: actions/checkout@v4.0.0
       - uses: maadhattah/combine-dependabot-prs@main
         with:
           branchPrefix: "dependabot"

.github/workflows/linter.yml

@@ -39,7 +39,7 @@ jobs:
       # Checkout the code base #
       ##########################
       - name: Checkout Code
-        uses: actions/checkout@v3.6.0
+        uses: actions/checkout@v4.0.0
         with:
           # Full git history is needed to get a proper list of changed files within `super-linter`
           fetch-depth: 0