chore(deps): update dependency c8 to v9 (#1480)

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

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [c8](https://togithub.com/bcoe/c8) | [`^8.0.1` -> `^9.0.0`](https://renovatebot.com/diffs/npm/c8/8.0.1/9.0.0) | [![age](https://developer.mend.io/api/mc/badges/age/npm/c8/9.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/c8/9.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/c8/8.0.1/9.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/c8/8.0.1/9.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>bcoe/c8 (c8)</summary>

### [`v9.0.0`](https://togithub.com/bcoe/c8/blob/HEAD/CHANGELOG.md#900-2024-01-03)

[Compare Source](https://togithub.com/bcoe/c8/compare/v8.0.1...v9.0.0)

##### ⚠ BREAKING CHANGES

-   **build:** minimum Node.js version is now 14.14.0

##### Features

-   **build:** minimum Node.js version is now 14.14.0 ([2cdc86b](https://togithub.com/bcoe/c8/commit/2cdc86bd0ac67ecf0f700212dc5f8a830ff9164f))
-   **deps:** update foreground-child to promise API ([#&#8203;512](https://togithub.com/bcoe/c8/issues/512)) ([b46b640](https://togithub.com/bcoe/c8/commit/b46b6401274488db5b1027a78090257095ae4f72))
-   **deps:** use Node.js built in rm ([2cdc86b](https://togithub.com/bcoe/c8/commit/2cdc86bd0ac67ecf0f700212dc5f8a830ff9164f))

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "after 9am and before 3pm" (UTC), Automerge - At any time (no schedule defined).

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

♻ **Rebasing**: Whenever PR is behind base branch, 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/nodejs-logging).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4xMDMuMSIsInVwZGF0ZWRJblZlciI6IjM3LjEwMy4xIiwidGFyZ2V0QnJhbmNoIjoibWFpbiJ9-->

package.json

@@ -74,7 +74,7 @@
     "@types/sinon": "^10.0.0",
     "@types/uuid": "^9.0.0",
     "bignumber.js": "^9.0.0",
-    "c8": "^8.0.1",
+    "c8": "^9.0.0",
     "codecov": "^3.6.5",
     "gapic-tools": "^0.3.0",
     "gts": "^5.0.0",