Minor fixes for dependency compatibility

[iggyvolz]

A couple minor fixes for the v2 branch:

• Depends on revolt/event-loop ^0.1 instead of ^1 (other projects use ^1 so composer refused to install the "conflicting" packages)
• coroutine() => async(), TimeoutCancellationToken => TimeoutCancellation as per https://github.com/amphp/amp/releases/tag/v3.0.0-beta.1
• Various renames as per https://github.com/amphp/byte-stream/releases/tag/v2.0.0-beta.1

[kelunik]

Thanks!