message: Add Node version support policy to README
diff: @@ -22,6 +22,38 @@ Each module provides release notes in `modules/*/RELEASE_NOTES.md`.
  The release notes for the `core` module are [here](https://github.com/BitGo/BitGoJS/blob/master/modules/core/RELEASE_NOTES.md).
  +# NodeJS Version Support Policy
  +
  +We only support [Long-Term Support](https://github.com/nodejs/Release) versions
  +of Node starting with [Node 8.9.0 (LTS)](https://nodejs.org/en/blog/release/v8.9.0).
  +
  +We specifically limit our support to LTS versions of Node, not because this
  +package won't work on other versions, but because we have a limited amount of
  +time, and supporting LTS offers the greatest return on that investment. It's
  +possible this package will work correctly on newer or older versions of Node.
  +
  +As each Node LTS version reaches its end-of-life we will remove that version
  +from the node engines property of our package's package.json file. Removing a
  +Node version is considered a breaking change and will entail the publishing of
  +a new major version of this package. We will not accept any requests to support
  +an end-of-life version of Node. Any merge requests or issues supporting an
  +end-of-life version of Node will be closed. We will accept code that allows
  +this package to run on newer, non-LTS, versions of Node. Furthermore, we will
  +attempt to ensure our own changes work on the latest version of Node. To help
  +in that commitment, our continuous integration setup runs the full test suite
  +on the latest release of the following versions of node:
  +* `6`
  +* `8`
  +* `10`
  +* `11`
  +* `lts`
  +
  +JavaScript package managers should allow you to install this package with any
  +version of Node, with, at most, a warning if your version of Node does not fall
  +within the range specified by our node engines property. If you encounter
  +issues installing this package, please report the issue to your package
  +manager.
  +
  # Notes for Developers
  See [DEVELOPERS.md](https://github.com/BitGo/BitGoJS/blob/master/DEVELOPERS.md)
  