2019-10-21, Version 12.13.0 'Erbium' (LTS)

This release marks the transition of Node.js 12.x into Long Term Support
(LTS) with the codename 'Erbium'. The 12.x release line now moves into
"Active LTS" and will remain so until October 2020. After that time, it
will move into "Maintenance" until end of life in April 2022.

Notable changes:

npm was updated to 6.12.0. It now includes a version of `node-gyp` that
supports Python 3 for building native modules.

PR-URL: https://github.com/nodejs/node/pull/29981