Bump actions/checkout from 4 to 5

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/haskell-ci.yml

@@ -143,7 +143,7 @@ jobs:
           chmod a+x $HOME/.cabal/bin/cabal-plan
           cabal-plan --version
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           path: source
       - name: initial cabal.project for sdist

.github/workflows/nix-flake.yml

@@ -18,7 +18,7 @@ jobs:
     name: Nix on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: wimpysworld/nothing-but-nix@main
       with:
         hatchet-protocol: 'rampage'
@@ -52,7 +52,7 @@ jobs:
     name: Nix on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: wimpysworld/nothing-but-nix@main
       with:
         hatchet-protocol: 'rampage'

.github/workflows/update-flake-lock.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Install Nix
         uses: DeterminateSystems/nix-installer-action@main
       - name: Update flake.lock