deps: update actions/github-script action to v7 (#1311)

[![Mend Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/github-script](https://togithub.com/actions/github-script) | action | major | `v6` -> `v7` |

---

### Release Notes

<details>
<summary>actions/github-script (actions/github-script)</summary>

### [`v7`](https://togithub.com/actions/github-script/compare/v6...v7)

[Compare Source](https://togithub.com/actions/github-script/compare/v6...v7)

</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 this update again.

---

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

---

This PR has been generated by [Mend Renovate](https://www.mend.io/free-developer-tools/renovate/). View repository job log [here](https://developer.mend.io/github/googleapis/java-storage-nio).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy44MS4zIiwidXBkYXRlZEluVmVyIjoiMzcuODEuMyIsInRhcmdldEJyYW5jaCI6Im1haW4ifQ==-->

.github/workflows/approve-readme.yaml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository_owner == 'googleapis' && github.head_ref == 'autosynth-readme'
     steps:
-      - uses: actions/github-script@v6
+      - uses: actions/github-script@v7
         with:
           github-token: ${{secrets.YOSHI_APPROVER_TOKEN}}
           script: |