Respect Promise implementation; performance; v2.0.2

- Respect fetch.Promise in the body.
- Improve performance of Body.text() by avoiding the allocation of another
  Promise in the common case of wrapping a Buffer.
- Release v2.0.2

Release v2.0.1

1.5.3

1.5.2

1.5.1

1.5.0

1.4.1

1.4.0