Update for futures v0.3.0-alpha.15

[Nemo157]

Remove FutureObj usage and futures_api feature

Blocked on an http-service release with http-rs/http-service#23

Description

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[Nemo157]

@yoshuawuyts any chance of an http-service-mock v0.2.0 release? That's the only remaining blocker for this.

[yoshuawuyts]

@Nemo157 published!

[Nemo157]

I've had to add a hack to the Cargo.toml to workaround a breaking change in ascii-canvas v1.0.1, there appears to already be an open issue about it so this can be removed once it gets yanked.

EDIT: Resolved and hack removed.