Bump actions/checkout from 2 to 4 (#94)

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-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>

.github/workflows/CI-OndaEDFSchemas.yml

@@ -28,7 +28,7 @@ jobs:
         arch:
           - x64
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: julia-actions/setup-julia@v1

.github/workflows/CI.yml

@@ -26,7 +26,7 @@ jobs:
         arch:
           - x64
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: julia-actions/setup-julia@v1

.github/workflows/Documentation.yml

@@ -9,7 +9,7 @@ jobs:
     name: Documentation
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: "Update dependencies"
         # Only use a released version of dependencies when creating documentation for a tag
         if: ${{ github.event_name != 'push' || !startsWith(github.ref, 'refs/tags') }}