feat!: Support Node 18+ (#1879)

* 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 `engines` and minor functionality

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Daniel Bankhead <[email protected]>
Co-authored-by: d-goog <[email protected]>

Author: gcf-owl-bot[bot]

.kokoro/continuous/node14/common.cfg

@@ -4,7 +4,7 @@
   "description": "An example of using puppeteer to orchestrate a Google sign in flow.",
   "main": "oauth2-test.js",
   "engines": {
-    "node": ">=12"
+    "node": ">=18"
   },
   "scripts": {
     "start": "node oauth2-test.js"

.kokoro/presubmit/node14/common.cfg

@@ -24,11 +24,7 @@ export function warn(warning: Warning) {
   }
   warning.warned = true;
   if (typeof process !== 'undefined' && process.emitWarning) {
-    // @types/node doesn't recognize the emitWarning syntax which
-    // accepts a config object, so `as any` it is
-    // https://nodejs.org/docs/latest-v8.x/api/process.html#process_process_emitwarning_warning_options
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    process.emitWarning(warning.message, warning as any);
+    process.emitWarning(warning.message, warning);
   } else {
     console.warn(warning.message);
   }

samples/puppeteer/package.json

@@ -114,19 +114,10 @@ describe('pack and install', () => {
    */
   afterEach('cleanup staging', async () => {
     if (!keep) {
-      if ('rm' in fs.promises) {
-        await fs.promises.rm(stagingDir, {
-          force: true,
-          recursive: true,
-        });
-      } else {
-        // Must be on Node 14-.
-        // Here, `rmdir` can also delete files.
-        // Background: https://github.com/nodejs/node/issues/34278
-        await fs.promises.rmdir(stagingDir, {
-          recursive: true,
-        });
-      }
+      await fs.promises.rm(stagingDir, {
+        force: true,
+        recursive: true,
+      });
     }
   });
 });