Dont use all (default) features for the tracing crate

[JAicewizard]

This adds a lot of dependencies, even for non-wasm targets. For https://github.com/linebender/druid this seems to be around ~24 added deps.

[JAicewizard]

I can file a PR tomorrow if this would speed up fixing this

[colelawrence]

@JAicewizard thanks for bringing this up! I'm not super familiar with feature settings in Cargo.toml.

If you set that up in a PR I'd do my best to merge it quickly and make a release for you! It would be great to have our library help with the linebender project.

[colelawrence]

I tried it out on our repo here at Storyscript, and disabling default features for tracing and tracing-subscriber didn't break anything, so I made that update and pushed a new release 0.2.0 from master branch.

Please feel free to share feedback!

[JAicewizard]

Looks good, I will test when I get the time for it. thank you!