feat!: drop support for older Node

Author: metcoder95

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [16.x, 18.x, 19.x, 20.x]
+        node: [18.x, 20.x, 21.x]
     name: Node ${{ matrix.node }}
     steps:
       - uses: actions/checkout@v4

package.json

@@ -16,7 +16,7 @@
     "release": "npx standard-version --no-verify"
   },
   "engines": {
-    "node": ">=16.0.0"
+    "node": ">=18.0.0"
   },
   "keywords": [
     "fastify",