Upgrade to tracing-subscriber 0.3

[bertof]

Updated the library to use the newer tracing-subscriber traits.
Changed the least amount of code possible and tested checking for regression.
Bumped the library version as the interfaces have changed.

[hlb8122]

Thanks very much. Aiming for a release sometime this week. Will make sure to include this.

[bertof]

You're welcome! Thank you for this library, it's really easy to use.

[hlb8122]

I did a little jiggle around before 0.6. Do you mind rebasing against lastest master, this should work

            let span = ctx.current_span().id().and_then(|id| {
                ctx.span_scope(id).map(|scope| {
                    scope.from_root().fold(String::new(), |mut spans, span| {
                        // Add span fields to the base object
                        if let Some(span_object) = span.extensions().get::<HashMap<Cow<'static, str>, Value>>() {
                            object.extend(span_object.clone());
                        }
                        if spans != String::new() {
                            spans = format!("{}:{}", spans, span.name());
                        } else {
                            spans = span.name().to_string();
                        }

                        spans
                    })
                })
            });

            if let Some(span) = span {
                object.insert("_span".into(), span.into());
            }

[bertof]

I've updated my PR.

[hlb8122]

@bertof Thanks

[hlb8122]

@bertof Released in 0.6 👍