chore(deps): update dependency @types/node to v20 (#1177)

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

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [@types/node](https://togithub.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/node) ([source](https://togithub.com/DefinitelyTyped/DefinitelyTyped)) | [`^18.0.0` -> `^20.0.0`](https://renovatebot.com/diffs/npm/@types%2fnode/18.18.6/20.8.8) | [![age](https://developer.mend.io/api/mc/badges/age/npm/@types%2fnode/20.8.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/@types%2fnode/20.8.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/@types%2fnode/18.18.6/20.8.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/@types%2fnode/18.18.6/20.8.8?slim=true)](https://docs.renovatebot.com/merge-confidence/) |

---

### 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/cloud-debug-nodejs).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4zMS4yIiwidXBkYXRlZEluVmVyIjoiMzcuMzEuMiIsInRhcmdldEJyYW5jaCI6Im1haW4ifQ==-->

Author: renovate-bot

package.json

@@ -73,7 +73,7 @@
     "@types/mocha": "^9.0.0",
     "@types/mv": "^2.1.0",
     "@types/ncp": "^2.0.3",
-    "@types/node": "^18.0.0",
+    "@types/node": "^20.0.0",
     "@types/proxyquire": "^1.3.28",
     "@types/semver": "^7.0.0",
     "@types/tmp": "^0.2.0",

system-test/fixtures/sample/package.json

@@ -16,6 +16,6 @@
   "devDependencies": {
     "gts": "^2.0.0",
     "typescript": "4.8.4",
-    "@types/node": "^18.0.0"
+    "@types/node": "^20.0.0"
   }
 }