tracing-error v0.2.0

This is a breaking change release in order to update the
tracing-subscriber dependency version to the v0.3.x release
series.

Changed

• Updated tracing-subscriber dependency to v0.3.0 (#1677)

Fixed

• Disabled default features of the tracing dependency so that
  proc-macro dependencies are not enabled (#1144)
• Documentation fixes and improvements (#635, #695)

Added

• SpanTrace: Added SpanTrace::new constructor for constructing a
  SpanTrace from a Span passed as an argument (rather than capturing
  the current span) (#1492)

Thanks to @CAD97 for contributing to this release!