libp2p-wasm-ext 0.23.0

Allows passing in an external transport in a WASM environment
Documentation
# 0.23.0 [2020-10-16]

- Update `libp2p-core` dependency.

# 0.22.0 [2020-09-09]

- Update `libp2p-core` dependency.

# 0.21.0 [2020-08-18]

- Update `libp2p-core` dependency.

# 0.20.1 [2020-07-06]

- Improve the code quality of the `websockets.js` binding with the browser's `WebSocket` API.

# 0.20.0 [2020-07-01]

- Updated dependencies.
- Support `/dns` in the websocket implementation
  ([PR 1626]https://github.com/libp2p/rust-libp2p/pull/1626)