chore(deps): bump actions/checkout from 2 to 4 (#39)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -29,7 +29,7 @@ jobs:
     steps:
     # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
     - name: Checkout Repo
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Gradle Wrapper Validation
       uses: gradle/wrapper-validation-action@v3.5.0