deps: Update actions/checkout digest to eef6144 (#497)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | digest | `692973e` -> `eef6144` |

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Never, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/GoogleCloudPlatform/genai-databases-retrieval-app).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzOC45Ny4wIiwidXBkYXRlZEluVmVyIjoiMzguOTcuMCIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOltdfQ==-->

Co-authored-by: Yuan <45984206+Yuan325@users.noreply.github.com>

.github/workflows/labels.yaml

@@ -23,7 +23,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
+      - uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
       - uses: micnncim/action-label-syncer@3abd5ab72fda571e69fffd97bd4e0033dd5f495c # v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}