Bump actions/checkout from 3 to 4

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>

.github/workflows/ci.yaml

@@ -11,7 +11,7 @@ jobs:
   ormolu:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: haskell-actions/run-ormolu@v13
   build:
     runs-on: ubuntu-latest
@@ -23,7 +23,7 @@ jobs:
     env:
       CONFIG: "--enable-tests --enable-benchmarks --flags=dev"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: haskell/actions/setup@v2
         id: setup-haskell-cabal
         with: