chore(deps): update github actions to v5 (major) (#1129)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v4.2.2` -> `v5.0.0` |
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v4` -> `v5` |

---

### Release Notes

<details>
<summary>actions/checkout (actions/checkout)</summary>

###
[`v5.0.0`](https://redirect.github.com/actions/checkout/releases/tag/v5.0.0)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v4.3.0...v5.0.0)

##### What's Changed

- Update actions checkout to use node 24 by
[@&#8203;salmanmkc](https://redirect.github.com/salmanmkc) in
[https://github.com/actions/checkout/pull/2226](https://redirect.github.com/actions/checkout/pull/2226)
- Prepare v5.0.0 release by
[@&#8203;salmanmkc](https://redirect.github.com/salmanmkc) in
[https://github.com/actions/checkout/pull/2238](https://redirect.github.com/actions/checkout/pull/2238)

##### ⚠️ Minimum Compatible Runner Version

**v2.327.1**\
[Release
Notes](https://redirect.github.com/actions/runner/releases/tag/v2.327.1)

Make sure your runner is updated to this version or newer to use this
release.

**Full Changelog**:
https://github.com/actions/checkout/compare/v4...v5.0.0

###
[`v4.3.0`](https://redirect.github.com/actions/checkout/releases/tag/v4.3.0)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v4.2.2...v4.3.0)

##### What's Changed

- docs: update README.md by
[@&#8203;motss](https://redirect.github.com/motss) in
[https://github.com/actions/checkout/pull/1971](https://redirect.github.com/actions/checkout/pull/1971)
- Add internal repos for checking out multiple repositories by
[@&#8203;mouismail](https://redirect.github.com/mouismail) in
[https://github.com/actions/checkout/pull/1977](https://redirect.github.com/actions/checkout/pull/1977)
- Documentation update - add recommended permissions to Readme by
[@&#8203;benwells](https://redirect.github.com/benwells) in
[https://github.com/actions/checkout/pull/2043](https://redirect.github.com/actions/checkout/pull/2043)
- Adjust positioning of user email note and permissions heading by
[@&#8203;joshmgross](https://redirect.github.com/joshmgross) in
[https://github.com/actions/checkout/pull/2044](https://redirect.github.com/actions/checkout/pull/2044)
- Update README.md by
[@&#8203;nebuk89](https://redirect.github.com/nebuk89) in
[https://github.com/actions/checkout/pull/2194](https://redirect.github.com/actions/checkout/pull/2194)
- Update CODEOWNERS for actions by
[@&#8203;TingluoHuang](https://redirect.github.com/TingluoHuang) in
[https://github.com/actions/checkout/pull/2224](https://redirect.github.com/actions/checkout/pull/2224)
- Update package dependencies by
[@&#8203;salmanmkc](https://redirect.github.com/salmanmkc) in
[https://github.com/actions/checkout/pull/2236](https://redirect.github.com/actions/checkout/pull/2236)
- Prepare release v4.3.0 by
[@&#8203;salmanmkc](https://redirect.github.com/salmanmkc) in
[https://github.com/actions/checkout/pull/2237](https://redirect.github.com/actions/checkout/pull/2237)

##### New Contributors

- [@&#8203;motss](https://redirect.github.com/motss) made their first
contribution in
[https://github.com/actions/checkout/pull/1971](https://redirect.github.com/actions/checkout/pull/1971)
- [@&#8203;mouismail](https://redirect.github.com/mouismail) made their
first contribution in
[https://github.com/actions/checkout/pull/1977](https://redirect.github.com/actions/checkout/pull/1977)
- [@&#8203;benwells](https://redirect.github.com/benwells) made their
first contribution in
[https://github.com/actions/checkout/pull/2043](https://redirect.github.com/actions/checkout/pull/2043)
- [@&#8203;nebuk89](https://redirect.github.com/nebuk89) made their
first contribution in
[https://github.com/actions/checkout/pull/2194](https://redirect.github.com/actions/checkout/pull/2194)
- [@&#8203;salmanmkc](https://redirect.github.com/salmanmkc) made their
first contribution in
[https://github.com/actions/checkout/pull/2236](https://redirect.github.com/actions/checkout/pull/2236)

**Full Changelog**:
https://github.com/actions/checkout/compare/v4...v4.3.0

</details>

---

### 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**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about these
updates 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/googleapis/genai-toolbox).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS42MC40IiwidXBkYXRlZEluVmVyIjoiNDEuNjAuNCIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOltdfQ==-->

Co-authored-by: Averi Kitsch <akitsch@google.com>

.github/workflows/tests.yaml

@@ -62,7 +62,7 @@ jobs:
           go-version: "1.22"
 
       - name: Checkout code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           repository: ${{ github.event.pull_request.head.repo.full_name }}