Bump actions/checkout from 2 to 4 (#506)

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>

Author: dependabot[bot]

.github/workflows/test-legacy-compilers.yaml

@@ -45,7 +45,7 @@ jobs:
           NGROK_AUTH_TOKEN: ${{ secrets.NGROK_AUTH_TOKEN }}
           SSH_PASS: ${{ secrets.SSH_PASS }}
       - name: Checkout Source
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Activate Ruby 2.7
         uses: ruby/setup-ruby@v1
         with:

.github/workflows/test-legacy-upgrade.yaml

@@ -45,7 +45,7 @@ jobs:
           NGROK_AUTH_TOKEN: ${{ secrets.NGROK_AUTH_TOKEN }}
           SSH_PASS: ${{ secrets.SSH_PASS }}
       - name: Checkout Source
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Activate Ruby 2.7
         uses: ruby/setup-ruby@v1
         with: