.github: 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] <[email protected]>

.github/workflows/e2e.yaml

@@ -22,7 +22,7 @@ jobs:
     timeout-minutes: 30
     steps:
       - name: Check out
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install namespace
         run: |

.github/workflows/test.yaml

@@ -16,7 +16,7 @@ jobs:
         with:
           go-version: ${{ matrix.go-version }}
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           path: main
       - name: Setup cross-invocation caching