Tag a New Release? (0.5.1/0.6.0)

[carwyn]

There's a been a huge amount of work since 0.5.0 back in January 2019. It would be great to get this out as a release. This is especially the case since Go modules have become ubiquitous now and consumption of this library will default to 0.5.0 rather than master unless users are explicitly requesting it. This also means that people will be using random points in the master branch which could make supporting the library more time consuming.