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](actions/checkout@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>

Author: dependabot[bot]

.github/workflows/validatePullRequest.yml

@@ -13,7 +13,7 @@ jobs:
     env:
       solutionName: Microsoft.Graph.sln
     steps:
-      - uses: actions/checkout@v3.6.0
+      - uses: actions/checkout@v4.0.0
       - name: Setup .NET
         uses: actions/setup-dotnet@v3.2.0
         with: