Bump actions/checkout from 3 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -14,7 +14,7 @@ jobs:
   complement-internal:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3 # Checkout complement
+      - uses: actions/checkout@v6 # Checkout complement
       - uses: actions/setup-go@v4
         with:
           go-version-file: go.mod
@@ -54,7 +54,7 @@ jobs:
             timeout: 10m
 
     steps:
-      - uses: actions/checkout@v3 # Checkout complement
+      - uses: actions/checkout@v6 # Checkout complement
 
       - uses: actions/setup-go@v4
         with: