chore!: move to node 14 as minimum version (#457)

* chore!: move to node 14 as minimum version

* refix docs

* update kokoro files to node 14

* Update sync-repo-settings.yaml

* Update ci.yaml

* 🦉 Updates from OwlBot post-processor

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

---------

Co-authored-by: sofisl <55454395+sofisl@users.noreply.github.com>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

.github/sync-repo-settings.yaml

@@ -9,9 +9,9 @@ branchProtectionRules:
       - "ci/kokoro: System test"
       - docs
       - lint
-      - test (12)
       - test (14)
       - test (16)
+      - test (18)
       - cla/google
       - windows
       - OwlBot Post Processor

.github/workflows/ci.yaml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [12, 14, 16, 18]
+        node: [14, 16, 18, 20]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3

package.json

@@ -5,7 +5,7 @@
   "main": "./build/src/index.js",
   "types": "./build/src/index.d.ts",
   "engines": {
-    "node": ">=12.0.0"
+    "node": ">=14.0.0"
   },
   "repository": "google/node-gtoken",
   "scripts": {
@@ -49,11 +49,11 @@
     "@types/mocha": "^9.0.0",
     "@types/node": "^18.0.0",
     "c8": "^8.0.0",
-    "gts": "^3.0.0",
+    "gts": "^3.1.1",
     "linkinator": "^4.0.0",
     "mocha": "^9.2.2",
     "nock": "^13.0.0",
-    "typescript": "^4.6.4"
+    "typescript": "^5.1.6"
   },
   "files": [
     "build/src",