build(deps): 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](https://github.com/actions/checkout/compare/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/test.yml

@@ -10,7 +10,7 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: cachix/install-nix-action@v23
     - name: Add keys group (needed for go tests)
       run: sudo groupadd keys

.github/workflows/update-vendor-hash.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ github.actor == 'dependabot[bot]' }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0

.github/workflows/upgrade-flakes.yml

@@ -8,7 +8,7 @@ jobs:
   createPullRequest:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install Nix
         uses: cachix/install-nix-action@v23
         with: