[v8] drop node 18 (#1366)

## Description

This pull request updates the project's Node.js version requirements and
related configuration files to use Node.js 20 or newer, and removes
support for Node.js 18. These changes help ensure compatibility with the
latest Node.js features and security updates.

**Node.js version updates:**

* Updated the required Node.js engine in `package.json` from `>=18` to
`>=20`.
* Changed the `@types/node` development dependency in `package.json`
from version `~18` to `~20`.

**CI/CD workflow updates:**

* Modified the matrix in `.github/workflows/ci.yml` to run tests only on
Node.js versions 20, 22, and 24, removing Node.js 18.
* Updated the Node.js version used in
`.github/workflows/fix-latest.yml`, `.github/workflows/release.yml`, and
`.github/workflows/runtime-tests.yml` from 18 to 22.
[[1]](diffhunk://#diff-942585ab102b61d7fc2b3ebd901f78b627f006e4fe9ed539189fce8bfc503740L23-R23)
[[2]](diffhunk://#diff-87db21a973eed4fef5f32b267aa60fcee5cbdf03c67fafdc2a9b553bb0b15f34L22-R22)
[[3]](diffhunk://#diff-8240caaafb609c069828d284a282ebeb4f57b1ce1668ab60c97ad12412dfeb6dL12-R12)

## Documentation

Does this require changes to the WorkOS Docs? E.g. the [API
Reference](https://workos.com/docs/reference) or code snippets need
updates.

```
[ ] Yes
```

If yes, link a related docs PR and add a docs maintainer as a reviewer.
Their approval is required.

Author: nicknisi

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [18, 20, 22, 24]
+        node: [20, 22, 24]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4

.github/workflows/fix-latest.yml

@@ -20,7 +20,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18
+          node-version: 22
           registry-url: 'https://registry.npmjs.org'
 
       - name: Install Dependencies

.github/workflows/release.yml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18
+          node-version: 22
           registry-url: 'https://registry.npmjs.org'
 
       - name: Install Dependencies

.github/workflows/runtime-tests.yml

@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version: 22
       - uses: denoland/setup-deno@v2
         with:
           deno-version: v1.x

README.md

@@ -11,7 +11,7 @@ See the [API Reference](https://workos.com/docs/reference/client-libraries) for
 
 ## Requirements
 
-Node 18 or higher.
+Node 20 or higher.
 
 ## Installation
 

package-lock.json

@@ -9,7 +9,7 @@
     "workos"
   ],
   "engines": {
-    "node": ">=18"
+    "node": ">=20"
   },
   "type": "module",
   "main": "./lib/cjs/index.cjs",
@@ -54,7 +54,7 @@
     "@types/cookie": "^0.6.0",
     "@types/glob": "^8.1.0",
     "@types/jest": "^29.5.14",
-    "@types/node": "~18",
+    "@types/node": "~20",
     "@types/pluralize": "0.0.33",
     "@types/qs": "^6.14.0",
     "@typescript-eslint/parser": "^8.25.0",