2020-12-15, Version 14.15.2 'Fermium' (LTS)

Notable Changes:

- **deps**:
  - upgrade npm to 6.14.9 (Myles Borins)
    https://github.com/nodejs/node/pull/36450
  - update acorn to v8.0.4 (Michaël Zasso)
    https://github.com/nodejs/node/pull/35791
- **doc**: add release key for Danielle Adams (Danielle Adams)
    https://github.com/nodejs/node/pull/35545
- **http2**: check write not scheduled in scope destructor (David Halls)
    https://github.com/nodejs/node/pull/36241
- **stream**: fix regression on duplex end (Momtchil Momtchev)
    https://github.com/nodejs/node/pull/35941

PR-URL: https://github.com/nodejs/node/pull/36476