Bump actions/checkout from 3 to 4 (#364)

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

.github/workflows/test.yml

@@ -25,15 +25,15 @@ jobs:
     name: Code format
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: scalafmt
         run: ./sbt scalafmtCheckAll
   test_scala_3:
     name: Scala 3
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'temurin'
@@ -50,7 +50,7 @@ jobs:
     name: Scala.js
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'temurin'