feat!: Support Node 18+ (#650)

* chore: Support Node 18+

* feat: Support Node 18+

* chore: Additional Node 18 upgrades

* chore: don't change test fixtures

* feat: Move kokoro directories to 18

* chore: Update checkout and setup-node to v4

- https://github.com/actions/checkout/releases/tag/v4.0.0

- https://github.com/actions/setup-node/releases/tag/v4.0.0

Source-Link: googleapis/synthtool@c19dd80
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-nodejs:latest@sha256:8060aba1f6d5617d08091767141ab2a99ea1ccbd9371fd42ffc208c5329caa73

* chore: Update .OwlBot.lock.yaml

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: bump to Node 18

* chore: bump to Node v18

* chore: remove Node 14 references

* chore: temp remove `NPM_CONFIG_PREFIX` from samples-test

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: create `NPM_CONFIG_PREFIX` if it doesn't exist

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: mkdir -p if `NPM_CONFIG_PREFIX` does not exist

* chore: install `npm@10`

* chore: verify npm `10.7`

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: npm debugging

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: more npm debugging

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: npm debugging

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: npm debugging

* chore: npm debugging

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: additional debug logs

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: remove `NPM_CONFIG_PREFIX`

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: more debugging

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: `npm` set prefix

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: npm@10

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* chore: use pre script for npm i for now

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Daniel Bankhead <dan@danielbankhead.com>
Co-authored-by: Daniel Bankhead <danielbankhead@google.com>

Author: 3 people

core/packages/gaxios/package.json

@@ -32,7 +32,7 @@
     "google"
   ],
   "engines": {
-    "node": ">=14"
+    "node": ">=18"
   },
   "author": "Google, LLC",
   "license": "Apache-2.0",