Bump minimum Node version to 18.17, upgrade undici (#3959)

* build(deps): bump undici from 5.28.4 to 6.19.5

Bumps [undici](https://github.com/nodejs/undici) from 5.28.4 to 6.19.5.
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.28.4...v6.19.5)

---
updated-dependencies:
- dependency-name: undici
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* BREAKING: Set minimum Node version to 18

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Felix <188768+fb55@users.noreply.github.com>

.github/workflows/ci.yml

@@ -25,7 +25,6 @@ jobs:
       fail-fast: false
       matrix:
         node:
-          - 16
           - 18
           - 20
           - 22

package.json

@@ -123,7 +123,7 @@
     "parse5": "^7.1.2",
     "parse5-htmlparser2-tree-adapter": "^7.0.0",
     "parse5-parser-stream": "^7.1.2",
-    "undici": "^5.28.2",
+    "undici": "^6.19.5",
     "whatwg-mimetype": "^4.0.0"
   },
   "devDependencies": {
@@ -155,7 +155,7 @@
     "vitest": "^2.0.5"
   },
   "engines": {
-    "node": ">= 16"
+    "node": ">=18.17"
   },
   "tshy": {
     "esmDialects": [