the "engines" for `@elastic/transport` and `@elastic/elasticsearch` says node `>=18` is supported, but uses undici@7

[trentm]

% npm ls undici
asdf.20250424t102536@1.0.0 /Users/trentm/tmp/asdf.20250424T102536
└─┬ @elastic/elasticsearch@9.0.0
  └─┬ @elastic/transport@9.0.1
    └── undici@7.8.0

% rg -A1 engines node_modules/@elastic/*/package.json
node_modules/@elastic/elasticsearch/package.json
56:  "engines": {
57-    "node": ">=18"

node_modules/@elastic/transport/package.json
74:  "engines": {
75-    "node": ">=18"

Undici v7 officially dropped support for Node.js v18.
Is the intent that v9 of the JS client raises the min-supported Node.js to v20? If so, the "engines" should be updated.

Thanks.

[JoshMock]

Good catch. I need to write a CI test that breaks when engines rules are violated to keep this from happening. 🤦

My original intention was to wait for 9.1 or 9.2 to officially drop 18.x support, but with 18.x hitting EOL on April 30 it's tempting to retroactively decide 9.0 will just not support it, since it's a natural place to introduce the breaking change. Will ponder on that over the weekend and get back to this next week.

[JoshMock]

I've opened #260 and elastic/elasticsearch-js#2827 to drop support for Node 18. This change will go out in client 9.1 and transport 9.1. 18 will still be supported by v8.x clients indefinitely.