chore(deps): bump actions/checkout from 3 to 4 (#18)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

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

.github/workflows/continuous-integration.yml

@@ -28,7 +28,7 @@ jobs:
 
     steps:
       - name: "Checkout repository"
-        uses: "actions/checkout@v3.5.3"
+        uses: "actions/checkout@v4"
 
       - name: "Check formatting (clang-format)"
         uses: "jidicula/clang-format-action@v4.11.0"
@@ -51,7 +51,7 @@ jobs:
 
     steps:
       - name: "Checkout repository"
-        uses: "actions/checkout@v3.5.3"
+        uses: "actions/checkout@v4"
 
       - name: "Install Criterion"
         run: |
@@ -95,7 +95,7 @@ jobs:
 
     steps:
       - name: "Checkout repository"
-        uses: "actions/checkout@v3.5.3"
+        uses: "actions/checkout@v4"
 
       - name: "Install Valgrind"
         run: |
@@ -149,7 +149,7 @@ jobs:
 
     steps:
       - name: "Checkout repository"
-        uses: "actions/checkout@v3.5.3"
+        uses: "actions/checkout@v4"
 
       - name: "Install Criterion"
         run: |
@@ -204,7 +204,7 @@ jobs:
         run: ${{ matrix.deps-command }}
 
       - name: "Checkout repository"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@v4"
 
       - name: "Create temporary directory"
         run: cd "$(mktemp -d)"