Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -15,7 +15,7 @@ jobs:
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v5    
+      uses: actions/checkout@v6    
 
     - name: Add $GOPATH/bin to PATH
       run: echo "$(go env GOPATH)/bin" >> $GITHUB_PATH

.github/workflows/dependabot-weekly-automerge.yml

@@ -12,7 +12,7 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Merge clean Dependabot PRs
         run: |
           set -euo pipefail