2021-02-23, Version 12.21.0 'Erbium' (LTS)

This is a security release.

Notable changes

Vulnerabilities fixed:

- **CVE-2021-22883**: HTTP2 'unknownProtocol' cause Denial of Service by
    resource exhaustion
- **CVE-2021-22884**: DNS rebinding in --inspect
- **CVE-2021-23840**: OpenSSL - Integer overflow in CipherUpdate

PR-URL: https://github.com/nodejs-private/node-private/pull/256