document latest NodeJS LTS / minimum version support (22.18.0)

### Summary

Coming out [this PR](https://github.com/ProjectEvergreen/greenwood/pull/1543), the latest `engines` setting for Greenwood will now be, and supporting any current / latest LTS version
```json
"engines": {
  "node": ">=22.18.0"
},
```

### Additional Details

_No response_

### Greenwood Issue

https://github.com/ProjectEvergreen/greenwood/issues/1379