Bump version to 1.2.1

Bump version to 1.2.0

Bump version to 1.1.4

Bump version to 1.1.3

Bump version to 1.1.2

Bump version to 1.1.1

Merge pull request iaintshine#2 from iaintshine/codecs

Implement `Tracer#inject` and `Tracer#extract` OT methods

Merge pull request iaintshine#1 from iaintshine/initial-implementation

Initial implementation of Test::Tracer